Let's start with some of the glaring cons: The music and the graphics are pretty much awful. The music tries for orchestral dramatic latin chorus, but it's simply grating on the dungeon crawl. Sprites are pretty grainy and the dungeons themselves are pretty badly drawn and difficult to distinguish.
But that's not why people want to play SMT games anyways, it's just an added bonus when it does happen. The combat for people unfamiliar with SMT is your protagonist and three given demons in a battle, and aside from that it's a traditional RPG/Dungeon Crawler. Demons are tameable and fusable and it's really interesting in this version too, as you can fuse within the dungeon itself and keep moving along. There's also a few added features that make the dungeon crawl interesting, such as a layouts that change when you turn around, doors that disappear, invisible walls, and the whole nine yards. You also search for various "forma" which is basically your item crafting materials, which makes wandering around the dungeons a bit nicer. Fusing demons has never been easier, as you can see what abilities will be inherited and what won't, as well as copying the abilities of another demon and adding them in as well, via Demon Sources. It's fairly intuitive and certainly is miles away from the good luck in fusing needed in other titles.
Plot wise, there is a really interesting concept, and it gets a full work out. You are essentially a Space Marine
, at first, but then you start wandering through alternate realities full of demons and it just gets crazy. The only real fault against the plot is that the three branches typical to an SMT game, Law, Order, and Neutral, are very blatantly obvious and telegraphed from miles away.
All in all, I'd say if you're interested in SMT games, but have never played one before, this is not a bad place to start. It's not a bad game, but there are a lot of flaws and things that would probably repel some people. I picked it up for $20 as something to tide me over until the March games come out, and it's holding my interest. Definitely something at least worth looking into.