I have been playing Armies of Arcana for 4 years now and I would easily recommend it for 5 reasons:
1) it can be played in 15mm or 25mm
2) there is a wealth of support for it, an email list, an easy-to-navigate website with tons of stuff for AoA, and the designer of AoA is devoted to helping new players
3) there are 18 official armies, some unofficial ones and a clear, balanced system for creating your own troops and monsters
4) the rules are easy to learn, allow for a vast variety of battles and they make sense
5) it is a lot of fun to play
Please feel free to email me with any other questions you have about Armies of Arcana - frogstar168@yahoo.com
Justin