We've found ourselves more interested in Dungeons & Dragons: Arena of War [Free] than we typically are when it comes to Mobage's ultra-free to play offerings, because, well, Dungeons & Dragons. It's a great IP with decades worth of history behind it, and it feels like the App Store is perfect for a really awesome title that takes D&D style tabletop game play and uses all the great things that have come of iOS gaming to make something truly great. I'm imagining Pocket Heroes but with a real budget and recognizable IP behind it.
Unfortunately, Arena of War is not that, or anything close to that. Instead, it seems to borrow Squids' fling mechanic dressed up nicely with some D&D trimmings and doused with free to play. It's an odd mix, and our forum community reaction is incredibly varied. Regardless, like all Mobage games these days, it's free to try so if you have a love for D&D source material it's at least worth a download.