I don't have any direct experience with them, but my uncle bought a reman Pontiac V6 from them, and it lasted longer than the factory motor. I've read quite a few good things about them from non-affiliated sources. I've also seen pictures of their production facility in Southern Indiana (as well as driven by it), and the assembly laboratory was essentially a surgical clean room. The main building that they have in Jasper, IN, was really nice looking from the outside, alot newer than it really was.
I THINK that a local racing series uses relatively stock, sealed chevy small block 350s that Jasper builds. They run them all season long with only fluid changes, and they are nice motors.
HTH!