I have been on 4.3 since the leak came out..flashed N3bula, Sophisticated and am on Nephilium now. I was a Beans devotee for a long time on 4.1.2 and will definitely be trying 23 when it comes out.
All that said, I can only point to one noticeable improvement with 4.3 and that is apps to SD card (I never wanted to do an SD card swap). If anything I have given up a bunch of features from Beans 22 that I liked. Hopefully 23 will be everything from 22 and more on 4.3.
Devices previously Rooted and Rommed: Charge, Captivate, Nook Color, Lenovo IdeaPad A1, DINC, Razr Maxx