I have been auditioning a few amps to pair with my Yamaha 1060 and B&W CM8s + CMC to power my front stage (I have a powered sub as well). The two I have liked the best in my price range are the Outlaw 5000 and the Emotiva XPA-3 with the Emotiva slightly edging out the Outlaw.
While my Yamaha could power the speakers just fine for volume, the external amplifiers just do a better job of giving a bigger feel to music and keeping the sound tight and clean. In my demo songs things like drum hits, general bass, and vocals were much sharper, cleaner, and just felt more effortless.
The one potential worry I have is that the Emotiva is rated at up to 275wpc. The CM8s are rated at 150W RMS but also sometimes 150W peak depending on where you look. I don't anticipate cranking the volume much above -15db which means I will likely never really hit that full power draw, but should I worry about my speakers with this combination under my anticipated listening conditions?
I enjoy the sound out of the Emotiva enough that I could try going with their BasX line but that's a pretty significant power downgrade for their 5-channel version. The Outlaw sounded great but if both are safe I'd stick with Emotiva.