One of the feature I'd like to know more about on the Ultra is it's (dedicated "sealed" mode). 
Seems to me this would be a perfect sub for music and movies.
		
		
	 
I wouldn't count on using that feature at all... you will lose a bunch of headroom, and its a ported sub....    Not a sealed sub...    They claim you can seal it, but the data is out so far about performance in that mode so far... Or at least I would be using it...
If your spending that kind of money on a sub...  get the ultra...   
I have a plus/2 and a Plus in the same room, and they are great....   tons of bass, House Shaking to say the least...    I was considering getting Dual Ultra 13's, but I am going to try my hand at DIY...    with some really high quality drivers...
The New Ultra is stated to have roughly the same amount of output as the Plus/2 but sound quality is much better...   Plus/2 may have a little more output above 30hz, but the Ultra 13 with have much better performance in the less then 30hz range and with subsonics...     
SVS makes a phenomenal product...    Fit and Finish are top notch..   as well as customer service...
Good luck on your choice.....