Martin Logan Grotto or Depth?

I just ordered over a month ago a Martin Logan Grotto. It still is on back-order and have been considering buying the Depth instead. My HT consists of B&W704s Left and Right, 602 backs and a Lcr600 center. I haven't really used my system yet because of the missing subwoofer but I already know I will be upgrading my speakers soon.
What is the difference between the two subwoofers? And which one should I buy?
Frankly,I'd go for the Depth...or the Descent! The Grotto lacks the punch of a Depth and although it may be more expensive, it's definitely worth it.
It all depends on your room size and your listening preferences.

Martin Logan makes a fast and accurate subwoofer. Nothing replaces moving air to feel your listening room with bass. Tricks to make small subwoofers sound large only muddy the sound.

If your room can take it, go Depth . . . . my new listening room is larger than my previous one and that is the direction I am headed. I will match the Depth to my Thiel CS 1.6s and expect to have a natural musical experience.