As for the others:
- iPad - Proprietary, locked down, no.
- Honeycomb tablets - I'm not spending $400+ to be a beta tester.
- Non-Honeycomb Android tablets - They all seem a little lacking, dontchathink? Plus they all run a version of Android really not suited to the environment.
- PlayBook - Proprietary OS, no.
- 1024x600 screen. Actually, in fairness, the rest of the hardware is very nice.
- "Unofficial" port of Honeycomb is somewhat lacking, in large part because of the lack of source code to Honeycomb itself.
- It probably sounds like I'm cheating and mentioning the first two points again, but Honeycomb 3.0 was designed for a 1280x800 screen. While 3.1+ relax that requirement, the UI hasn't changed that much, and it's still reasonable to think 1024x600 is too small.