I own and like a Popcorn Hour A-110, but I don't agree with all the web pages that say it plays everything.
Below is list of things I've tried to play that cause the player to freeze. In each case I ripped the DVDs using k9copy (a straight copy, no recompression or size/quality reduction). When I try to play the resulting ISO files the player freezes, does not react to the remote control, and has to be power-cycled.
Bis ans Ende der Welt, second of three DVDs. The first and third DVDs play perfectly.
Once upon a time in the west, I think this is the same DVD, but I can't find the DVD right now.
A Charlie Chaplin compilation which doesn't seem to be available any more.
There are also some DVDs that can't be played when ripped with the Mac Disk Utility, I think Best of Dave Allen suffered from this.
Everything ripped with AnyDVD and CloneDVD can be played. I think I know which tool the Popcorn Hour developers use…