I'm having trouble picking a favorite out of these. The three of them as a whole is rather impressive in design and concept. Halatali kinda makes me wish there would be an extreme mode of it though. The Battle Arena concept just makes me feel all sorts of happy, and I like the feeling that it's competition, not life or death.
AT, is just plain creepy. Diabolos fight is interesting on several levels.
For me, Braflox's Longstop Hard was the weakest of the bunch, yet still very much fun. The only thing I miss in the design of all of these is that the dungeons are a bit short, though, that's by design. I just hope that eventually they come out with exploration mode dungeons that are designed to withstand long periods of time being spent within.
Still, loads of fun. I'll be smiling while I'm grinding these.