I first saw Monster Wars a little while ago at Macworld as Liv Games was just publishing it, but the title has been out for a little while now and I've had a little longer to play with it. Monster Wars is not only another huge content pack for Legendary Wars, with tons of new stages, modes and units to play with, but it is a nice iteration on the series as a whole, with a lot of subtle but solid improvements to the gameplay.
Unit animations are generally better across the board, and the controls work basically the same. I still sometimes have trouble keeping track of which heroes I'm controlling and which lanes they are supposed to be in. The UI is much improved. The pacing of the game shows that Liv Games has learned quite a bit about how to move players from level to level. The new modes add quite a bit to the game, which was likely a tough task considering how much variety was already there.
If you loved Legendary Wars, you've probably already grabbed this one. But even if you've never heard of Legendary Wars, Monster Wars is a steal at 99 cents. New players might be slightly overwhelmed by what's going on in the new title, but Liv Games has made two really spectacular titles here.They really shouldn't be missed, especially on the iPad.