A friend is doing a complete 7.1 channel system with marble 9.0's. I've heard and measured the 9.0, and it's quite good.
But understand that any system using very small midwoofers, even when paired with something as good as a SVS sub will not allow you to reach "reference" levels of output. So if that's not an issue then go for it. If it is then look at a different company that uses more/bigger drivers.
Also the ScanSpeak tweeters will handle high power, but be very very careful not to clip the amp!
I'm sure Michael Barnes would disagree with me but I've been building speakers longer than he has......
For $950 for all 5 speakers, it is about as good as it gets. I would actually look at the ceramic 4.0 setup instead - cleaner sound, better midrange detail, and $100 cheaper. Cross them at 80hz to a good sub and they will play very loud, but not reference levels, like Tom noted (but neither will the SVS without bottoming out, so the 4.0's won't be the "limiting" factor in your system, regardless). For the price and size, I have not personally heard anything better (or anything that really comes close, for that matter).
I just love my 5.1/4.0 set-up. Once you set up relevant cross-over with your sub (I use Hsu VTF-2)then you are in musical/HT heaven. I bought mine before the marble & ceramic versions were introduced, so For HT/music, I'd recommend ceramic 4.0 set-up.
You will not go wrong with Norhs-go ahead and buy'em