[G2 General] lavafire:
I have been jumping between a few ROMs for a period of time now and finally decided to stick with one which I think is stable, fast and gives the best battery life by far. I admit I haven't tried all of the ROMs out there, also people have different set ups and use their phone differently. So please take what I say as a recommendation only, and I mainly wish to share some of my experience as I know how frustrating it can be to choose a ROM out of so many choices. At the end I also want to share the MODs I have been using and how I have personalized my device, hopefully will help someone out there.

Note: I didn't use the same MOD for all ROMs! See more explanation below.

ROM

Just to make it clear, I wipe all before flashing a new ROM. I don't use any kind of backup software, yes that is right I don't, call me insane :P But the result of poor battery life or restart/FC should not be caused by these factors. I also install about the same app back (give a take a couple which I don't use often) after a flash. I also use the same set up for all my ROMs e.g. Auto brightness, screen on time and etc.

STOCK

I have been on stock LG G2 ROM for about 5 months I think, there are some nice features and I have to say it is probably the most stable ROM out there.

But for me, I experienced a bit of lag here and there.

I think many out there will agree with me, when I say the ROM doesn't have the best UI design. I would recommend installing Xposed Installer (xda) and G2 Xposed (play store) and make some modifications yourself.

The battery is ok, last a day for me and ends up with 30% on a good day (often below 15%).

The biggest feature for me is the knock code to unlock device, I do miss it.

I didn't compare but the Camera app is better than Google Camera (opinion, didn't test).

CloudyG3 v1.3

Used this ROM for about a month, stable enough for daily driver.

Some lags when using the phone in general. Animation slow down is the main reason I decided to go with another ROM.

UI looks much nicer than G2 since it is based on G3.

Can use G3 TweaksBox to tweak UI like you can with G2 Xposed, but most features will require you to pay. Which I did, but don't think it is worth the money. Most changes require you to reboot to see effect and it is buggy.

Again knock code is a plus, better than stock ROM I think.

Slightly better battery than Stock but not much better, I would say about the same. Been using the same MODs since.

Camera is also pretty good, on par with STOCK (opinion, didn't test).

Mahdi-ROM 09/20

This is a very popular recommendation, rated the most stable ROM. But it is the opposite for me, phone would restart and FC.

Some bugs listed on ROM page. This doesn't affect me, but may affect some of you.

Very similar to CM11, a lot of options to tweak, too much in my opinion.

Battery life about same as stock, again the ROM wasn't stable enough for me so can't possibly have amazing battery life. Same MODs as I have now.

No knock code.

ParanoidAndroid 06/28

This is my current ROM, glad I decided to try it.

Very stable, haven't had a single FC or restart yet and I have been on it for weeks.

This is the fastest ROM, I don't notice any animation slow down at all. Ok a few times with the keyboard I am using but pretty sure it is the keyboard app.

Amazing battery life. e.g. 10 hours since unplugged, 2 hour screen on, 76% left.

Has double tab to wake, but no Knock code :(

Good amount of built-in customization

MODs + app suggestions

Twilight app (or something similar), for less harsh light on the eye when reading at night.

Google Now Launcher + Xposed GEL Settings, I like the Google Now being included in the launcher itself.

LiOn Tamer (AKA Unbounded) to stop wake-locks, just install and then done no set up require.

Silence app, which turns phone silent for those who work at from 9am - 5pm.

Calendar + Calendar Mute app which turn phone silent for those who are at University with odd lecture times.