Which sub would you choose?

As someone who's Sold Wilson for years, I think what you have here is a case where you can EASILY spend way more money than you'll possibly get back sonically if you're not careful here! Bass is the single most system set up factored, room placement critical(as well as seating location corespondingly), acoustically challenged, an EXPERIENCE dependent factor!!! You can MOST ASURADLY spend the money you're talking about spending, and get EASILY MUCH BETTER PERFORMANCE and sonics from a much cheaper sub, set up by a knowledgeable, skilled, EXPERIENCED individual!...I can't understate this enough!
I guess what I'm saying is that, from someone who sells the WatchDog, it's a very good woofer by itself. Is it worth what is sells for sonically? In my oppinion, no. But then that's me. If you can afford the money, than I think you should buy one. But make no mistake about it, you won't get $10k+ worth of world class bass out of a single Watchdog, just because you have the woofer!!!!!!...that is correct. World class bass doesn't come from great woofers, it comes from the skilled technician who's putting your sytem together, placing your woofers(or speakers), and calibrating your bass in your room!!
I've seen/heard it hundreds, even thousands of times before! People buy the best products and the most expensive money can buy, and they don't get the performance they're capable of most alsways!...not by a long shot when it comes to bass performance in a given room!
My suggestion might be to buy A COUPLE (or more)excellent high performance, yet more reaonably price woofers, like maybe M&K's excellent MX5000's. Revel's B15 or whatever, even Velodyn's FSR 18's will sufice. I hear excellent things about the Pricy Whise Profounder, which is still way less than a Wilson Woofer if you must pay a ton for ONE WOOFER!!! You could even spend far less on SEVERAL WOOFERS, PROPERLY SET UP OF COURSE(carefull, or Phase cancellation is an issue), and buy like a bunch of Paradigm Servo 15's! Heck, 4 of those would only be a little over $6k new, and you'd have way more to work with sonically! MOre dynamic ease, potentially quicker response, better transient attack, smoother bass response in the room, and a more effortless dynamic overall!..not to mention they're musical subs on their own.
Acually, there's a lot of excellent subs. But I'd probably buy 2 or 3 of the Thiel subs at less than the Wilson's single sub price, and get potentially much better results driving em for L/C/R's, before I bought a $10k sub. Again, just a perspective.
At any rate, do what you need to do. I just don't see the value in the performance that woofer offers for such a rediculous price. Especially when you consider it's only ONE WOOFER!!...which already has it's challenges and draw backs or limited applications effectively.
Also, I need to ask who's setting up and calibrating the woofer for you? And, how exeperienced are you at setting up systems properly? I've just been over to too many audiphiles home's, who own very expensive TRICK subs, only to hear what' DEFINITELY sub-par top caliber bass performance! And we're talking just about every time here!! It's never anything to write home about.
Here, once again, it all comes down to knowing what you're doing with the right gear, especially with woofers and bass performance. If you don't have someone who's going to do it for you, then I HIGHLY SUGGEST you invest some SERIOUS time to learning how to make a subwoofer proplerly integrate and work into your room and system!...this one make take more time to learn than you think for really really good results in small acoustic spaces like these!
Good luck

I think foreverhifi offers some very good advice. I have listened to the Watchdog, and it is an excellent subwoofer, but how much better is it at $10k vs a very good $3k sub. You could spend less and buy 2 sub woofers. Two are much easier to place and get a flat response. The other aspect is the Revel uses a parametric EQ, similar to our PARC design. This can really help bass mode problems with subs, and large speakers and allows proper speaker room integration very easily. Using subs now is now very common as their designs have gone from being the HT booming thing to something that really adds that last octave in a musical way. But it's integration with the rest of the system and the room is what is key to achieving that musical quality as well as the HT boom--even in HT it should come across as natural and not just a motor box in the corner. There are two things I would direct you to that might be helpful. Both on our website, www.rivesaudio.com Go to the listening room. In the speaker section there is a download for speaker placement, and it goes into subwoofer placement and 2 vs 1 subwoofer. The other area is to click on the modes, and this describes the bass modes that can be caused by any low frequency interaction with the room. As stated, we design a PARC that compensates for this problem, but Revel has wisely incorporated this same type of technology in their B-15 subwoofer. I don't think it's as sophisticated as what we have done, but it is cost effective and very useful for sub integration. (Yes, our PARC can be used for other subwoofers as well).

How about the Aerial? Best sub I've ever heard. $10K for a $700 woofer in a big box? No way.

I have a wilson sub in my listening room right now sitting next to a velodyne 18, I will tell you that I think the velodyne is better regardless of price, and I will be taking the wilson back to the store. I have to say also that I am a wilson puppy 6 owner and love them set up with atma-sphere mp1 pre and ma2 amp. I have not heard a system that I like better. I am also very sure there is a better system in many a home.