I like my AX. I also have a 137MD and a RTS II.
I don't mind the size of the AX as it's very similar to the DLSRs. For a motor-driven camera, it's quiet. The best thing, for me is that the autofocus is fairly quiet and allows the easy use of polariser filters on lenses that used to have front elements that rotated as they were focused, such as the Vario-Sonnar 35-70mm. If you take the lens off the infinity setting for closer focusing, then you will have that extra 10mm extension to work with. Rough focus the lens, such as the VS 35-70 in macro mode, or a Macro-Planar, and then the autofocus does the rest for you.
I must admit when using the camera on a tripod, I keep forgetting to use the viewfinder blind to keep stray light out, but that's a minor thing.
I also like the fact that I can plug in an external battery pack when the weather is cold. I've been using the 2CR5 Lithium batteries, but have purchased a charger and a rechargeable R2CR5, but have yet to have used it as I'm working through my supply of non-rechargeables.
The other minor quibble, was that the battery packed up, and even though I had one with me, I couldn't open the battery cover as I had a Kirk tripod-plate bolted to the bottom of the camera and I didn't have an allen key with me. I've now added that to my gadget bag.