Kal just reviewed the XPA-5 in Stereophile. I have not got my hands on the review but others have noted it was very positive. I use 3 XPA-1s and an XPA-5 with an all B&W media room. I find the Amps to be excellent. They give an effortless and nearly unlimited dynamic range to my blast away movies and the detail for just plain old movie watching is great. On a functional note, (not subjective), the noise floor is very, very low and really, the Emo's just get out of the way and do what they are supposed to do, amplify sound without coloration. It does seem that the 800 series, at least really opens up with a higher current higher power amp. I assume this is common among B&W's other range of speakers.
Now, I must say, they look like they were built by Stalin era manufacturing and 50s technology thermal control. Although well made, they are not really all that attractive. I find the look very retro and they are insanely heavy. they run cool to the touch and never seem at all tasked. The outlaws, someone else can comment on but I believe they are good amps from others posts.