I'm pretty excited about my 2nd try with Doit. On my 1st try, I didn't see the Nirvana "Area" feature that I really need and decided Doit was not for me.

However, after continuing to have sync problems on Nirvana's Android app (this made mobile use completely impossible for me), I decided to have another look at Doit:
1. Doit doesn't have the ability to set a tag or date on several items at once like it does for Project and Context. There are a number of posts here requesting it and I'm optimistic that this feature will be added soon.
2. Doit still doesn't have the "Area" feature like Nirvana, but it sounds like it's on the roadmap. For now, I'm using tags instead. It's just a bit more cumbersome, but I'm ok with it. Of course, I'd like to have the ability to set the area of multiple items at once - like can be done with Project or Context.
3. Filters and subtasks are a nice bonus over Nirvana.
4. Doit's Android app works!!! I had no idea how much productivity and sanity I was losing by not being able to update/review my tasks whenever and wherever I was! For me, this makes up for the relatively minor features I miss from Nirvana.
5. For icing on the cake, I discovered that I could import my Nirvana tasks into Doit. I exported my Nirvana tasks (400 tasks! Way too many, I know!) to a CSV file; Setup Excel filters so that I could create several different imports (Area = Home; Area = Work; Project = ReadPile; etc) for this to be done in steps. Set all START DATEs to 12/1/13; Removed all but the columns that would be imported into Google Calendar (START DATE, SUBJECT (Name), DESCRIPTION (Notes)); Imported to Google Calendar; Did the Doit-GCal sync; In Doit, filtered on date = 12/1/13 so that I could identify the freshly imported items; Multi-select and then set them to a Project and/or Context that lines up with the former Nirvana area.
I'm still working on some cleanup: removing the 12/1/13 dues dates one at a time; manual tagging one at a time.
6. And did I say the Android App works?!!!

Anyway, nice work Doit!
Bob