I've listened to both the Rainmakers and the Hawks. In fact, I had the Hawks in my HT system for a couple years. The Rainmakers have a surprisingly full sound for a speaker of its size, but does so with mid-bass exaggeration and some degree of congestion with louder passages. The Hawk is a much better speaker, with both better clarity and LF extension. In Totem's lineup, I like the Hawks and Arros best.
I used the Hawks in my HT system, without a subwoofer, to good effect. No real complaints, except I felt that Totems center channel speaker I was using wasn't as articulate as I'm would have liked. So I went with all PSB for my HT. Ive never heard of problems using Hawks with HT, BTW.
Hope that helps.