I shot with my N-TX last night and used the remote shutter feature. It had no trouble at over 50 ft, and I never had a misfire, or any other reliability issues. It was great.
I updated the firmware before going out to shoot last night. From what I understand, the AF assist is supposed to have been modified in the latest firmware upgrade. I tried getting focus in a dark environment both with and without the trigger's AF assist, and I couldn't see a difference. I'm not sure what was changed in the firmware on that part. I wasn't surprise though - I was shooting 2 black cars, in an unlit area, against a black background. Pretty much the worst situation for AF.
I like the TX so much better than my old SU-800. This is the only way to go on flash triggers for me. Now that these are available, I would never even consider Pocket Wizards, Radio Poppers, or anything like those. These are actually reliable all of the time, and the metering stayed correct for every shot. I even left it in TTL, rather than setting it in manual, and just moved the flashes around. If they were going to have an issue, that would have found it. I am extremely happy with the new YN system.
What I need Yongnuo to make now is a TTL monolight - something similar to either the WL x3200 or like an Einstein E640, but with the capability of using a YN-622 for TTL control, or with a YN-622 built into the unit. 
