The SE215 has more bass for sure, but I found that I liked the punchiness of the 012 more. The SE215's bass is slightly unrefined and uncontrolled compared to the 012. Also, the highs are much clearer with the 012's while the 215's have more forward mids. I wouldn't call the 012's mids recessed, just that the 215's mids are typical Shure in your face mids.
Ultimately, to me, they are both very close in terms of sound and I'll pick one of the other arbitrarily (well, the Shures were sent in for replacement, but that's another story). Build quality wise, I'd still go with the Shures, even though there are some problems with them cutting out, as the 012's have thin, rubbery, tangly cables while the Shures are built like a tank. I'd say that both are about equal in terms of comfort as well. Both also have great customer service and 2 year warranties as well.
In the end, they're both very similar and it really depends on whether you want quality over quantity in terms of bass, and whether you like the mid-centric Shure sound or are more concerned with detail and sharper highs. I don't think you can go wrong with either but you haven't really gone into detail about exactly what kind of sound you're looking for...