I'm not sure if you've read it yet, but Craigsub did a review of the x-sub over at the av123 forums - link
I'm thinking of getting one as well for apartment living and then eventually in some sort of 2 channel or computer setup.

You may want to look at this by Rocket. Link

Thanks so much for the x-sub review link. It looks awesome!

The X-dub was getting me really interested but I really don't want to deal with the auto-on problems it apparently has.

I've been running the x-sub for about a month now, and I haven't experienced the auto on problem.

The auto-on problem only shows up if you use the high level inputs and listen at moderate volumes. I only plan to use the RCA inputs so it should be fine for me. What size room do you use the X-Sub in?

Strangely enough, I use the high level inputs and listen at moderate levels! Soon, I hope to change out some gear and use the RCAs, and I can see if there is a difference. My room is roughly 11 1/2 X 11 1/2.

There does seem to be a bit of lag time when using the high level connections with the xsub. It doesn't seem to be too bad to me. I hope to change it over to the low level connections tomorrow when I pick up a Nad intergraded amp.

The lag time is hardly noticeable, at least to me. It's weird, but when I first got the sub I needed to turn the volume way up before it detected a signal. Now, everything seems fine and it gets a signal even at lower levels.

Now that I think about it, it may be the fact that I'm not constantly peeking behind the sub looking for the green light. After I sit down, I usually don't get up!

Which NAD are you getting? My only choice with my NAD integrated amp is to use the high level speaker connections to the X-sub.

Even still, I've got a couple mentions in here of no trouble with the auto-on to a whole lot over on av123. Sure you generally hear more negativity on the internet about an item as opposed to whats good but I've heard a lot of both and AV123 is internet direct so I'm still feeling an overwhelming majority of people are having issues with it.

I may order it anyway and try it out and see how it does. If it works I'll keep it. If not it can go back to the mothership.