[Sprint LG Optimus G] stevek216:
AOSP-Wide Bugs: These bugs apply to every AOSP rom, aka any rom in this post.

-Camera focus: Some camera daemon keeps running when it shouldn't, or doesn't run when it should, or something. But that's immaterial, the end result is that after closing and reopening any camera app, autofocus will not work. There's a workaround that involves running a script every time you need to use a camera app. This is the biggest bug for me, and is what keeps me on stock in spite of the Play Music problems.

-Audio over headset: Some users have reported audio problems when on the phone and using a headset. On the phone meaning in a call.

-GPS: If GPS isn't working, flashing a stock rom, getting a GPS lock, then flashing back should fix the problem

AOSP Based

- AOSP based. It's the general consensus that since AOSP is maintained by Google, it is the pure android experience and is what Google thinks their operating system should be. Google's motives are for the most part believed to be more for the end user's benefits, as carrier and manufacturer modifications are either (a) well meant but poorly implemented or (b) commercially motivated and irritating. Google wants its OS to be the best in the world, and many think that it is

Rom Name: CyanogenMod 10.1 (Unofficial)

Developer (for our phone): Shellnutt2 (Other people are certainly involved, I'm just listing whoever's name is on the thread, this goes for all roms)

Link: http://xdaforums.com/showthread.php?t=2189788

Brief Description: A source build (thanks jblazea50) of probably the most famous rom in the android world, though that may be debatable. AOSP goodness, plus some extras. Stable for the most part, and actively being worked on by our fabulous devs.

Pros:

- General advantages of running CyanogenMod can be found here http://www.cyanogenmod.org/about/features

- Reader's digest version? Customizable user interface, lockscreen, very themeable, powerful equalizer, and more...

Major Bugs: None. Only minor bugs, and they're being steadily ironed out.

Rom Name: EOS 4.0

NO LONGER UNDER ACTIVE DEVELOPMENT: This is not to say it's not a serviceable rom, but if you're looking for updates, look elsewhere.

Developer: teamEOS/rlasalle15

Link: http://xdaforums.com/showthread.php?t=2219393

Brief Description: Another AOSP based rom, that concentrates on stability. Implements some features of CyanogenMod, and some of its own. Maintained by teamEOS. (If it matters, this is my AOSP rom of choice)

Pros:

- Full feature list, copied from original thread

NX Gesture Navigation Bar

Custom Quick Toggles Tiles with Brightness & Volume Seekbars

Softkeys Long-Press Actions

Custom Navigation Bar Ring Quick Launch Targets

EOS Status Bar Toggles

Navigation Bar Color w/ Project Glass (Auto-Transparency, not the Google Project Glass :P)

Status Bar Color

Battery Indicator Mods

Clock Mods

T-Mobile Theme Engine

Hide System Bars

Performance Settings

Volume keys switch depending on rotation. So the volume up key is always either on the top or to the right of volume down. (Toggle-able)

Default Volume Control Stream (Ring or Media)

Advanced power menu with reboot options.

Eos Control Center

MORE...

- Reader's Digest version? Very themeable, like CM 10, EOS control center includes performance and UI tweaks all in a central place. The volume keys switch according to the orientation of the phone, resulting in a more intuitive volume control. Reboot options include reboot to recovery and bootloader, which is convenient if you spend a lot of time in recovery. Personally I'm paranoid about holding buttons down all the time, I don't want things to break or loosen or whatever, so software tweaks like that make me happy.

- You can turn off the screen off animation, which is something I like to be able to do. I couldn't figure out how to do this on CM10.1, please PM me or something if you know how and I'll amend this. When it's late at night and my room is dark, it's irritating to have the brightness very low but the screen off animation flashing very brightly.

Major Bugs: None aside from universal bugs.

Rom Name: AOKP (CAVEAT - I have not personally tried this rom. Take my opinions with a large grain of salt. Actually I've tried not to put my opinion in this part at all, just reporting what I've read)

Developer: spleef

Link: http://xdaforums.com/showthread.php?t=2235291

Brief Description: Stands for Android Open Kang Project. Another fork of AOSP, with its own special features and modifications. It's now a source build, boots up fine, runs well. Being very actively developed, so for the latest and greatest check the thread.

Pros:

- General AOKP features can be found here http://aokp.co/

Cons:

- Again, has its own feature set, but if you're looking for particular features then make sure you do your research and check out all of the roms available.

Major Bugs: None in addition to the universal ones.

Rom Name: Liquid Smooth

Developer: spleef

Link: http://xdaforums.com/showthread.php?t=2373267

Brief Description: LiquidSmooth is an aftermarket firmware based on the Android Open Source Project.

Dedicated to providing users with smooth, stable and fast ROMs. A Lightweight modified AOSP base, and then add the features you crave! (Quoted from thread)

What makes this ROM special?

It seems like the main differentiator with this ROM is how smooth it is, or purports to be. I tested it for a day or so, and found that it was indeed smooth, though I've yet to find a stuttery ROM for this phone. What I did notice was that there seemed to be a different set of animations, which may make things seem even smoother. It's hard to quantify smoothness, and what's smooth for me could be even smoother for you. Or less smooth. Or of comparable smoothivity. Smoov. Anyhow. Try it out.

Detailed Features:

SaberMod GCC 4.7

-O3 Optimizations

ARM Optimized String Handling Routines

Linaro and Code Aurora Optimizations

Customizable lock screen buttons/sliders

Chronus & Dashclock widgets

Customizable hardware and software keys

Transparent navbar and status bar

Customizable navbar ring

Navigation bar widgets

Customizable power menu

Notification power widget

Customizable quick settings panel

Status bar mods

Theme engine

Quiet hours

Volume rocker music controls

Full Rotation

Customizable battery and notification light

Don't enable GPS if the requesting app is blacklisted.

Add permission that allows cancelling notifications from other apps.

Notification cancellation fixes

Ensure install-during-restore is like install-then-restore

libdrm: fix bad strncpy / snprintf calls

Make contacts app aware of blacklist being disabled

Frameworks: a bit taste of android 4.3

Frameworks: add reset option to clock color and cleanup

Frameworks: activate qs and notifications toggle for navring

Correctly release lockscreen lock on tile destroy

Add an option to allow a (subtle) notification vibration during calls.

NotificationManager : Fix security exception

Frameworks: privacy guard fix UI freeze

Prevent notification acces via HALO on protected lockscreens

HALO: keep apps in recents

HALO: halo can save last position now

HALO: Minimal Style

HALO: Master Switch

HALO: Custom Colors

SMS: add middleware layer

Add Statusbar Quick Peek

Frameworks: Privacy Guard

Profiles: Add bluetooth triggers

FIx: Phablet UI NavBar in landscape

Profiles: Add 2g/3g connection option

Profiles: Add a profile picker activity

Speed up statusbar/notification drawer

Use sticky broadcast to convey torch state

Keep notification LED on while daydreaming

Add Settings shortcut to Interface Settings Activity

WebSettings: Move Liquid tag to the end of the user-agent

Show application's package name in the "App info" screen

Settings: fixed HALO options so now they stick and function

Close notification panel when swiping away the last clearable

Frameworks: Reduce Navbar, Navrings, Slimpie observer footprints

Don't bring home to the front if we're opening a floating activity

Profiles: Fix turning bluetooth on/off when its in intermediate state

Settings: Rename 'Power sounds' to 'Charging sounds' and add summary

custom PIE features

smart capture and true shot camera features

And Many More...

Disclaimer: I am merely human. I make mistakes. This guide is by no means comprehensive. If you see an error I've made, inform me! Through PM or thread response, whichever you deem more appropriate (though if you think a post wouldn't be constructive, I recommend a PM). But please do so politely. To borrow a phrase that a fellow XDA'er seems to be fond of (crwolv) and that I have become fond of as a result (fondness by association?), let's all be couth. I really really really dislike personal attacks that I see in the forums, and while I'm by no means immune to getting upset and posting in that state, I think resolving issues with another user is a great use for the PM feature.