Update: I had the Grotto in my house for a few days, played around with it, and I must admit, I wasn't too impressed. Tried various positions, levels (had it turned almost all the way up, still wasn't good), etc etc, just didn't work.
My conclusion: Given the geography of my room, the Grotto just didn't fit. My room is 20x20 with a 19 foot ceiling, and the room is open on one end towards the kitchen.
Next, I brought a STF-2 to see if that would fit in. In one word WHOA!, this thing has a serious PUNCH! I have it only at about a third of the way up, and it's enough. Recalibrated everything, and it seems to blend in perfectly. Now, of course, I'm wondering if the VTF-2/3 wouldn't be even better! . But seriously, I think this will do for now, if I need more bass later (I don't think I will, unless I move), I'll get something else. For $350 I don't think I could have done better.
FYI, I have Axiom M80 fronts, VP150 and QS8 surrounds, all powered by a Denon 3805.
Thanks for all the help, everybody.
