Good deal.
I just purchased and received one of the Superior XP O-320's through Aerosport. It has the roller lifter technology and is the best deal out there I found on a new experimental engine. Probably a better deal if you go fuel injection because that's the same price, a $4-5k savings over a newly built Superior from aerosport. These engines were built by superior and mine was built in December 2012. The engine is beautiful and the whole process only took a couple weeks.
One Downfall is they are not painted, alodined only, with anodized aluminum adapter parts. As seen on Aerosprt website.
The only thing I dislike is that there is no install manual, and barely an operators manual from Superior. It's for an O-360 actually. You'd think dropping $25k on an engine would come with a decent manual. Figuring out all the port and sensor locations is going to be some serious VAF time!
One unexpected benefit is the engine data plate say 91/96 UL fuel.