I haven't recommended (and still don't do; see below) LuberPlayer(HD) (AppStore links: iPhone / iPad) as it doesn't have even basic functionality like hardware playback of iOS-friendly video files (MOV, MP4, M4V).
As has been mentioned in THIS article, the previous version of the player was removed (most probably, on Dolby's request) from the AppStore several days ago because it supported Dolby's licensed technologies (most importantly, the widely used AC-3 audio format). It returned there today with the following update list:
As you can see, there's absolutely no mention of dropping AC-3 in the list at all. Which it did drop – otherwise, it wouldn't have been let back in the AppStore. Which is a pity, as the developers of most other players do warn their users not to upgrade to keep AC-3.
Now, it immediately exits when trying to playing back anything with an AC-3 track in it: unfortunately, not only files with just one AC-3 track, but also ones with other, iOS-friendly tracks (AAC) too; for example, the AAC + AC3 files HERE. The player immediately goes back to the main file selector upon tapping a file, let it be either an M4V or an MKV. This is also a major problem:
1, alternative, playable audio should be played even in files containing AC-3 tracks (in this case, the AAC + AC3 videos)
2, at least a dialog should be presented to the users saying “Sorry, AC-3 had to be removed on Dolby's request” so that they know why the player refuses to play it back.
(The previous version, 2.0.0, had absolutely no problems with the same files.)
All in all, as the hardware acceleration (along with a lot of other, essential things) is still missing from the player, I in no way recommend it at its current price ($2.99). Get something better – there are a lot of much better titles, some even much cheaper or for even free.