Need help deciding on a sub

[Dust]

I just upgraded my HT sound system (see signature). I love the Mirage speakers, but I'm not totally sold on the sub. I prefer a tight sub, something that you feel inside your chest, but not boomey.

I've been looking at a Definitive Technologies Supercube I, but have also been reading about the Elemental Designs subs.

My room is rather large; about 25x20 with vaulted ceiling. Again, I like a nice tight base.

For the ED, I'm looking at the A2-300, A3-300, and the A5-350.

I'm looking to spend up to $750. Any suggestions?

Thanks!