A very informative post, Woochifer -

The ML Dynamo is also well regarded, but it's a fundamentally different design because it uses a sealed box. And that distinction is crucial
I believe a sealed sub is precisely what i want; however, it's not what i have. I'm just wondering how adept the HSU will be at filling the role of something sealed.

But, the performance in your room also depends on the sub's compatibility with your room dimensions, the sub positioning, and the calibration.
This is very true. My rig is currently in a rather large (30x18 or so) rectangular room. The only catch is a wood stove and a phone booth on either side of my mains, preventing me from placing the sub there. I've got limited options and several peices of furniture in the way, precluding perfect placement. I've basically come to accept the acoustic flaws of the room.

I won't be here permanently though, and as such i'm not too concerned about mating the perfect sub to this particular room. I'd like to get something versatile and as close as possible to what i'd ideally like, i.e. a clean, musical bass note.

What's your budget if you buy new? Is there going to be any home theater use at all?
That depends on the market for a used, albiet in excellent condition, VTF-2. I may not even have to sell it if it fits my criteria well enough.

I would also be using it for HT on occasion, although musical performance would be paramount.