I own an iPad since a few weeks. For now I only use V Control as a Logic controller, it has the most control features of the three (but also the more expensive).
You can control plug-ins with it, but not instruments, only effects. Lots of key commands included as well as shortcuts.
I've been bothering the dev with questions (before and after buying it) and he was always nice and responsive to all my questions/requests.
Very easy to set up an adhoc connection thru wifi, and it's pretty fast actually. No noticeable latency here, using it together with other audio apps.
I'm pretty interested in Touch OSC for the alternative controls it can offer (for instruments etc). I think it's the only app that offers faders and knobs control desktop app. that I know of.
I also own a Zero SL MK2 (before that had a 25 SL MK1) and I find V Control waaaaaay easier/friendlier to use than Automap. I'd have gladly paid a few dozens €'s more for motorized faders on the SL, which is the biggest dealbreaker for a control surface imho.
iOS 4.3.5 is already out. Apple will probably launch iOS5 very soon which was announced weeks ago.
http://www.macrumors.com/2011/09/27/apple-issues-invitations-for-october-4th-iphone-media-event/
We'll know then what's next.
That's for my 2c.