No, they can definitely produce for HT (although I'm getting a sub from someone else). I haven't noticed anyone on their forums that are 'stereo' nuts. They're all using them in theaters (presumably of wildly varying sizes ;>). While my 3-row theater with 110" screen isn't crazy abnormal here at AVS, it's definitely not average (particularly with the ID speaker crows), so I guess we'll see how they do. David at Ascend said the Sierra's would have absolutely no problem driving my theater.
As for the surround issue, while my theater already has 2 M&K SS-500's for my side surrounds (which I'm not changing), the opinions vary greatly on rear surrounds - whether they should be dipoles or monopoles.
With my theater, side surrounds being dipoles is a must. People who say side-surrounds should be monopoles don't have a 25+ foot long room with 3 rows of seats. The people in the rows away from the surrounds would be WAY WAY off-axis.
As for the rear surrounds, well, like I said, everyone has an opinion. THX's latest recommendations are to have two monopoles placed close together - assuming you're using a Select-2 or Ultra-2 THX pre-amp/receiver using one of their ASA sound modes. My theater designer said the ASA Cinema mode just tries to make the speakers act like dipoles, but... rear channels particularly with 7.1 are increasingly becoming more discrete, so while a dipole might make sense for 6.1, I'm not convinced for 7.1. Of course, if the rear speakers are 3 feet behind the last row, is that all they're going to hear if its a monopole?
Yuck - I'm really torn, but I have to say, getting monopoles for the rears significantly opens up my purchasing options. Not that many companies produce dipoles these days.
If I was willing to spend more money at this point, my choices would (obviously) expand greatly. Perhaps Triad, Genelec, Atlantic Tech, etc. etc. I think most are just way overpriced (M&K included).
I looked at Aperion (and still may actually) because they offered a nice looking dipole, and was tempted to try their mains but ultimately was swayed by all the overwhelming positive press for all of the Ascends speakers (and a few comments about the Aperions being a tad shrill w/ their tweeters (bright/fatiguing high-end/etc - saw it mentioned in at least 3 or 4 reviews in different forms so it spooked me a tad). While some people might list a monitor type of speaker as 'bright' (perhaps because that's what the source actually sounds like!), the fact that it was repeated in several reviews worried me just a tad.
I have to say I *really* liked the vibe I got from the guy I spoke with at Aperion (and Ascend as well :>). They seem like a great company, so I'll probably go with them for the rear at least if I decide to go with dipoles in the rear.
As of now, I've got 3 Ascend Sierra-1's and an Outlaw sub on the way. I wanted an SVS sub, but none of their 12" box subwoofers would fit in the subwoofer opening I have in my proscenium. That left HSU but the model I wanted was 17" wide and my opening is just shy of 17" (and I didn't want to chance it). So I went with an Outlaw sub knowing it was designed by HSU anyway (and was just a very slight downgrade from one of their best) and would definitely fit...