[Galaxy Note 3 Original Android Development] DrPhant0m:
OK, I'll answer some of these if I can... but only since you called me out for a thanks. Also because I want to hit 100 posts and get "Senior" lol

First of all... I've got the Verizon version, so there may be nuances to your AT&T version that I can't relate to. (Can you use Google Wallet's tap-to-pay? I sure as hell can't.)

Next, I don't have the option of using a Nexus 5 on Verizon... but that would be a tough decision for me, as well. They're actually vastly different phones, considering the difference in screen size and the S-Pen. For me... Note vs Nexus would boil down to "big screen and S-pen" vs "Rom flexibility and low risk of bricking" The bigger screen on the Note could be a blessing or a curse. If you can't palm a basketball... you can't text one-handed on the Note 3.

Unlocking the bootloader and installing a custom recovery --CWM or TWRP-- are cake on the Nexus 5, compared to even the simplest stuff on the Note 3. Keep that in mind for your decision.

All of the following is assuming you stick with the Note... and also that you do not have the Developer's Edition of the phone. (You'd know if you did)

Answer 1

: Do you mean CWM = ClockworkMod [Recovery] ? I googled "CMW android" and all I could see was the Content Marketing World app... so I think you mean clockworkmod... If your AT&T Note 3 is anything like mine... then you simply can't install a custom recovery. The locked bootloader means you can't flash a new recovery. The best you can do is install SafeStrap, which uses code from TWRP recovery (http://teamw.in/project/twrp2). We'll say that TWRP and CWM are like the Ford and Chevrolet of Android recoveries. People have reasons to prefer one or the other. Further, when you say "which CMW..." I presume you mean which version. Normally, I'd say "the latest stable version" unless there's some inherent problem with that.

However... the final answer is... you can't install clockworkmod. Install safestrap instead. It's available in apk format, and there are lots of threads detailing how to install and use it.

Answer 2

: Refer to Answer 1. You can't install a custom recovery due to having a locked bootloader. Do not try to install it, either. You will do more harm than good, I can guarantee it.

Prologue to Answer 3

: Once you are rooted and you have safestrap installed... before flashing anything, make a backup. (Refer to the safestrap threads for more info on that) Once you make a backup... understand what the benefits, and more importantly... the LIMITATIONS of safestrap are. There's a STOCK rom slot... and you can create secondary rom slots. Only the STOCK rom slot will allow you to use the full breadth of your device storage... the latter secondary slots are all just partitions which (in my experience) are not large enough to fit all of the apps that you would want on a daily driver. For this reason... many people flash over the STOCK slot with a CUSTOM rom. *** I do not recommend you to do this as your first foray into using safestrap. Get used to using it and flashing roms to the secondary slot first.*** One of the BENEFITS to safestrap is the ability to try out custom roms (in a limited-storage capacity) without removing your stock rom. Do this first. Try before you buy.

Answer 3

: You read the prologue above, right? Good... In general... do NOT install a ROM that was intended for a device to be used on a carrier other than the one that you are going to be using it on. There are carrier-specific parts to roms that you NEED to make calls or use data... and other parts that you don't NEED, but you will be doing a huge disservice to yourself if they are missing. For the 99-percenters, this means that you should stick to roms that are made for your carrier, specifically. (Some roms are universal, and will adapt as necessary... but it's still made to work with your carrier, just as an option among other carriers) I cannot speak from experience on using AT&T or T-Mobile... let alone an AT&T phone on T-Mobile's service. So, first, I'll recommend that you ask someone that has done what you want to do (check both the T-Mobile- and AT&T-specific forums). Then I'll give you my opinion... and that would be: If you've converted an AT&T phone to work on T-Mobile... then you should probably flash a T-Mobile rom to your phone. Again... check with someone that knows for sure. That person is not me.

Answer 4

: For anyone to suggest a rom to you... it's as good as them telling you what car to drive. You might agree, but it's your preference that should make the decision. For me, personally... I'm on a stock rooted version of the initial Verizon firmware release, MI9. That means that there has been minimal changes to the OS the way that Samsung and Verizon intended. I pretty much achieved root, and stopped there. (Knox was disabled/removed during my root process... and I used Titanium Backup to freeze the OTA process after the dust settled so I won't accidentally update and lose root) All custom roms have been made using the latest firmware for my phone, as they should be... but I have my reasons for staying on the initial stock release... and they mostly have to do with not taking a chance of tripping knox or using kingo or vroot. (my decisions are only best for me. you might agree, but you don't have to. no biggie)

My recommendation for you... (without knowing much about you):

Use safestrap to your benefit and try out some custom roms in the rom slots ***SEE NOTE***, and keep your STOCK rom slot untouched in case of a bad flash or other issues with any of the custom roms. Eventually, you might feel comfortable flashing a custom rom into your stock slot. That's a pro-move right there, and should be handled correctly. How cavalier you want to be with it is up to you... but there are strategies for doing it as safely as possible, such that you always have a working stock rom slot and a backup of it, so you can get back to the way you started without a brick. (check the forums, I saw a thread on this)

***NOTE*** The base rom used to make a custom rom is important... I don't know the numbering of your firmwares, so let's call them inital, 2, 3... current. If you're on the initial, and you flash a rom based on 2, 3, etc... you are not fully converting your phone to a newer firmware. This is an important distinction to make with the Note 3, because fully updating your phone to a newer firmware may trip the knox counter (and void your warranty, violate you company security policy, or both), cause you to lose root, or worse. When you install an OTA update that fully updates your Note 3, you're rewriting the kernel as well as other constituent parts, probably losing root access... and (in the case of the Note 3) this is also irreversible. You can't downgrade. (another reason why I'm still on the initial firmware). Flashing a custom rom based on a newer firmware will only update certain modules of your phone, but not the kernel. There are sacrifices to this, including instability and incompatibility. Be careful if the installation instructions for a custom rom include "update to XXX firmware" as the first step, for these reasons. That's only the part of the story that says "this rom is the most compatible when you're already on XXX firmware" but it doesn't include the part that says "you might lose your warranty or root access as a result of the firmware update."

Since we can only install touchwiz-based roms... you don't have to worry about losing any of the functionality that Samsung and your carrier intended. Well, let me rephrase that... you won't lose any of the functionality THAT YOU WANT TO KEEP (translation... the "cool Note 3 features"). Bloat and knox security are likely to be jettisoned from any custom rom, since it's pretty widely accepted that those are unnecessary and unwanted, respectively.

If you have any questions, feel free to PM me... unless you think that asking and answering them publicly will be a benefit to the community. Coming from a long line of phones that were fully unlockable... I didn't know any of this Note3-specific stuff a few weeks ago, and it was only through helpful people and helpful posts that I've been able to piece it all together with confidence. Look at my post history, I asked my share of long-winded questions very recently.