I have it for my droid 2, and it's much better than the version I had a year ago on my feature phone. The only bug I've found so far involves making dining reservations. They have an error in the date picking function so you have to pick the day after the date you want from the calendar. It loops though, so selecting June 1 reliably gets you May 31st reservation times.
Attraction information is there, and you can sort the attraction list by "closest", "wait time" or "open". You can also filter the list by favorites, waits under 30 minutes, fireworks/parades/shows, characters, or some pre-selected lists. I'm thinking that I'll get good use out of this by adding what we want to do in a given morning/evening to the favorites list, then sort by wait time.
You can also view on a map rides with current wait times under 30 minutes, or your favorites and tapping them brings up the wait time information.
It does reminders, but not calendar-based (I'll use a google calendar reminder for ADRs). When you look at events (performers, fireworks, etc) it gives you the option to set a reminder for that that will alert you 15 or 30 minutes before the show starts.
Searching for dining reservations is faster using Mobile Magic on my Droid (via wifi) than it is on a nearly-new business-class laptop on the dining website.
Some of their information is bizzare, like to get from All-Star Movies to All-Star Music they suggest taking the bus to DTD, then catching a bus back. It -works-, but it's certainly not efficient.
It's a battery hog (it runs a lot of data and the GPS) such that using it plugged in, I drain the battery faster than it charges off a wall outlet. I don't know how it would be for "normal" use in a park, but I'll find out in a few weeks. The phone does get warm, but not as much as using google nav.
Not everything fits on the screen in portrait mode. In particular attractions that have a description, accessibility information, auxiliary aids, directions and favorites buttons - in order to use the favorite tab, I have to turn the phone 90 degrees.
The images are a little nonsensical at times. Philharmagic has a picture of Winnie the Pooh on its attraction screen, for example.
I've had a few scroll issues where tapping will scroll the screen instead of selecting. It looks like this is a race condition, so if I were more patient it would probably work better.
It doesn't integrate at all with the reservation information on the wdw website. You can put in your travel dates, but not your resort information, or your dining confirmations. That would be a very useful feature in the next revision.
For AK there's a little blurb about the various animals and it will tell you where to find them. Note that if you look at the map (from the animal's screen) you need to hit the menu soft key and either select "home" or "menu" to get anywhere else. You don't appear to be able to add animals to your favorites.
Characters are added to your favorites list on a per-park basis. So adding Mickey Mouse at MK doesn't mean that he'll show up on your AK favorites list.
Really though, most of those are fairly minor quibbles. It's improved in the last year, and the price is right for me at $2.