this may not be a fair comparison, but i just sold my xtreme 160 for the for a pro 250 ver1 which didn't come with a askoll pump. kept my sicce from my xtreme and put it on the pro.
ran the pro /w a sicce CV PW, there was too much water heading into the body. too turbulent to provide a stable skim unless the water line was mid way into the cup neck . feeding caused the foam head to die instantly.
pro /w MW(needs a remesh), seems to have a good air/water ratio, water line was at bottom of the neck. pulled out at least 5x the amount of dark skim vs the PW. I could raise the water line half way into the cup and still have a steady stream of tiny bubbles traveling up the neck.
IMO the pro's body is definitely a better body design. I'm assuming the new 300 /w the askoll pump will outperform the xtreme series. If I didn't get a steal on the pro 250 ($175:eek1: ), I would have upgraded to the xtreme 300.
guess my main point is if you go xtreme, go mesh. if you want hassle free, go pro.