The X-350 also uses zero feedback and the X-250 uses a little feedback in the design. The X250 is a good all aorund amp that can be used with box or other speaker types and the X-350 should only be used with box type speakers from what I was told.
I own the X-250 with B&W matrix 803s and it works great.
I own the X-250 with B&W matrix 803s and it works great.