[Galaxy Note 3 Q&A, Help & Troubleshooting] sirobelec:
Welcome to XDA.

I suggest you enter the development section and do like most of us - flash like a maniac until you find a ROM that suits your needs, looks the way you want, feels the way you want. :D

Still, let me sum it up. These are the main categories of ROMs for our beloved N9005:

1. TouchWiz ROMs.

Those are ROMs based on the official firmware that Samsung released for our phones. They keep between most and all features and apps that are originally offered by Samsung, and then some extras like even better battery life, slightly better camera shots with higher quality, to some small extent they're themed.

tl;dr

Pros:

+ Stable.

+ Good battery life.

+ All the functionality is kept.

Cons:

- In my opinion, while quite functional, TouchWiz is ugly as hell. :D

- Can be somewhat laggy at times.

- You can't mod as much as you want to.

2. AOSP ROMs.?

Those are ROMs based on the Android Open Source Project. Basically, these ROMs turn your device into a Nexus device and strive to bring the pure Android experience. Those ROMs are fast as hell, responsive, and very, VERY easily modified. On the other hand, those are ROMs made by enthusiasts, in some cases professional developers. Still, ROMs that are made from the ground up, and are largely still works in progress.

tl;dr

Pros:

+ Your phone running an AOSP ROM will be way faster than TouchWiz.

+ NO bloatware. I mean, all that Samsung bulls**t like ChatOn, Samsung Hub/Apps/Link/Group Play/Trip Advisor and some 20 others are NOT present on AOSP ROMs. :D

+ Much more open to modifications, including the way even non-system apps look. Like, you can have a dark themed Facebook and Instagram and whatever you use. :D

Cons:

- Battery life on those ROMs is generally not as good as on TouchWiz.

- While the phone is way faster, the camera experience is also not as good as on TouchWiz. The camera starts quite slowly and while the shots it takes are not bad, those taken on TouchWiz are visibly better.

- Like I said above, those ROMs are works in progress and may have bugs and while most of them are with status Stable by now and most major bugs are not present anymore, there might still be some annoyances.

3. Ported ROMs.

Those are ROMs based on firmwares originally made for other devices, in our case mostly other Samsung devices. The Note 4 (soon Note 5) and S6 have functionality not present even on stock ROMs, like the Galaxy S6's Theme Store. That way with a ported ROM you have access to that functionality while keeping all of the original functionality.

Pros:

+ Added even more functions.

+ With ported ROMs you can experience to an extent new devices without actually having to buy them. :D

Cons:

- Might be buggy. Making another phone's firmware work on yours is no easy task.

- Battery life might be strange. Good on some days and downright miserable on others. xD

Final instructions:

1. Welcome to XDA.

2. Read A LOT. When choosing a ROM, read EVERYTHING in the ROM thread's original post, and if there is something you want to know but is not answered in the original post, search through the thread, 95% of the cases someone else has asked your question and it has been answered.

3. After reading a lot and you believe you're ready for action, READ IT ALL OVER AGAIN.

4. When you're absolutely sure you're ready, start flashing. :D

gg gl hf