I think stock is so far running better than Kexec. Some things don't seem to be completed enough or currently working on the Kexec builds. Though I've only tried cm10 and AOKP.
Speaking of Kexec, is there any more work going into it other than the occasional nightly? Is there work on rebuilding the camera app? Any Devs working on custom kernels for the droid 4 kexec builds? I would love to be on a custom kernel, but most importantly I would love a kexec build with a working camera?
Also, how is work on the video recording quality going, on stock?