Haven't heard the Orb speakers, but I have a 3.1 setup consisting of 3 B&W M-1's and a Polk PSW10 (I know I know, barf, I'm looking to upgrade). It's driven by a Denon AVR-2309CI and I couldn't be happier the past year with the B&W's. The subwoofer is a different story and I'm dying to upgrade.
It should be noted that my setup is in a garden apartment living room thats about 20x25. the B&W's fill the room nicely and I can't wait to get another 2 so I can complete my 5.1 setup. We're moving into a single family home in the next month though and for some reason I've got the upgrade fever and am looking at bookshelf size speakers like the 685's or the Paradigm Studio 10's...we'll see how the M-1's fair in my new media room before I get ahead of myself!
When I demoed at my retailer I got an opportunity to checkout a few set of speakers in the size range of the B&W M-1's. What I can remember were a set of Anthony Gallo satellites that look a lot like those Orbs and all I can remember was, "Wow, they sound even smaller than they look." Thin, brittle, lacking in any sort of midrange and you can forget about bass.
However, the B&W M-1's sound so much fuller than their size would have you believe. I would recommend not skimping on a subwoofer like I did. It was an impulse buy, I was out of money at the time and haven't been able to upgrade my Polk PSW10.
I find the M-1's have excellent clarity for their price and when paired with a receiver that has Audyssey EQ they become even more revealing. Let's be honest, the M-1's aren't and will never be a replacement for an actual bookshelf speaker. But if you're looking for something in a stylish and sleek package that doesn't disappoint, then the M-1's are for you.