I've been a user of Anki since '07 or so. Ankidroid does what I need  it doesn't annoy me or crash  and is pretty easy to navigate and use. It brings the full power of SRS to mobile devices  so I can study anywhere  all for free. I'm truly thankful for the team that created and updates it voluntarily - you guys rock! (Edit: the version as of Feb 2016 is even better  I'm loving the improved UI!)
February 20 2016