[Verizon Samsung Galaxy S III] Comp625:
Yep, if you check Carbon ROM's website, they indicated that they are diligently working on 4.4.

For anyone who is currently using Touchwiz and is thinking about taking the "leap" toward an AOSP ROM -- I highly suggest it. Below are some stray observations after having used BoneStock 3.4, HyperDrive RLS16 and CleanROM 7 (all are Touchwiz ROMs based on Android 4.1.2). I'm using CarbonROM nightly 11/14 based on Android 4.3.1.

Speed: People aren't kidding when they say that EVERYTHING is way smoother with AOSP. Here are some examples...

- My Notifications Pull-Down was always a bit laggy with TW -- that is not the case with AOSP.

- Opening, switching, and closing apps is now instantaneous.

- On Touchwiz, my "Available Memory" (RAM) would hover around 30% on medium-use and sometimes dip to the 8-10% range.

- With AOSP, I'm averaging around 30-40% with lots of stuff open, or around 60% on light use right after rebooting. It goes to show that Touchwiz eats up a lot of memory by default. Note: I used and continue to use the "Greenify" app to suppress apps from staying in memory.

- I'm sure the bump in speed is also attributable to the custom Cyanogenmod kernal that is used in CarbonROM.

Signal: My girlfriend has an S4 and I was able to draw comparisons side-by-side against my S3. When I was still on Touchwiz, my signal strength was nearly identical to her S4. Since switching over to AOSP......

- According to the popular "Network Signal Info" app, my phone would consistenly hover around 4dBm to 8dBm

weaker

than my girlfriend's S4. For example, in weaker signal areas, she'll pull in -100dBm but I'll hover around -105dBm. In my opinion, the drop in signal quality is NOT a dealbreaker for moving over to AOSP. I have yet to drop a call or be unable to make a call in all of my usual places.

- Based on the graphs in the "Network Signal Info" app, her stock S4 was more 'stable' with signal strength, whereas I saw tiny fluctuations (+/- 1dBm to 3dBm) on my phone. Her signal flat-lined more often, which IMO, is a good thing. Note: both phones featured similar ASU's (the frequency at which the signal is being updated).

- For anyone who doesn't know, Samsung does not open-source its RIL code. So the signal code in AOSP is essentially "reverse-engineered" to work with the S3 -- hence why signal strength varies.

Camera: I always found the Touchwiz camera to be a nuisance to use. IMO, from a practicality perspective, the camera quality with AOSP seems to be the same.

- Pictures of my cat always came out blurry (poor low-light capabilities) or mis-focused under TW, and continues to be the case with AOSP.

- I also appreciate the 4.3 menu interface (e.g. click on the screen and with 1 thumb drag, I can change Exposure, White Balance, etc.). These settings were a nuisance to pull up on Touchwiz.

- Oddly enough, under both TW and AOSP, I was never able to successfully change Exposure value. A +2.0 or -2.0 did nothing to the end photograph.

- Mind you, I am a borderline pro-photographer, so I definitely know what I'm doing when it comes to Exposure values, White Balance, etc. :p

Bluetooth:

- On Touchwiz, I had a ton of Hands-Free call quality issues but my A2DP Media Streaming was fine. Callers would often say that my words and sentences were cutting out A LOT, and that I would sound robotic. I did a lot of reading online about widespread problems with Samsung's proprietary Bluetooth stack, as well as issues with Google's own Bluetooth stack seen in 4.2 and up (see this link as a good example).

- On AOSP 4.3.1, it looks like Google's Bluetooth stack works for me. Call quality is better (not perfect but at least usable now) and media streaming still works perfectly like it did before.

- IMO, Bluetooth compatibility is a hit-or-miss/luck-of-the-draw experience for most devices regardless of what Bluetooth stack being used.

- Also, if my phone is connected via Bluetooth but nothing is streaming, I can now initiate voice commands (e.g. in Google Now) and it works as it should. Before on Touchwiz, I had to begin streaming something (e.g. Pandora) in order for voice commands to work -- otherwise, it would stay stuck and not accept any speech.

I'm sure someone will say "cool story bro"...but I hope that my user testimonial will help those who are on the fence about jumping to an AOSP ROM!