I like Brett's performance... particularly that lumbering jig he always does... it's pretty cool
I think he fits in very well as far as the stage performances go. Heck, Brian Marshal usually just stood there anyway.
But as far as the musical aspects, so far I like what I hear. Check out the solo he had in the alcatraz video for What If... he really get into it and does well! I also would like to see him do some base tracks and get base back into Creed's music. Weathered was pretty poor in that department.