I use Aperture with my iPad. The way it works, when you select projects to go to the iPad, they show up under "Events" in the iPad Photos app. Any albums will go into the Albums section and of course, places works as expected.
So basically it works like you would expect, just mapping Aperture projects into the Events section on iPad.
Also, if you use stacks, only the selected/pick picture will get synchronized (like when publishing), not the whole stack. I'd have to double check to be sure, but am fairly certain of this. Personally I am happy about this as I use stacks as mini-projects anyway.
All-in-all it seems to work great and I really enjoy browsing a day's results on my iPad. The only thing I'd wish for is some way to mark pictures, flag, tag, or folders, anything like that, so I could do some preliminary work before sitting down with Aperture.