A couple years back I had heard a couple complaints about quality of some machining that was done on some engines of theirs, but I can't comment whether they were isolated incidents, or an ongoing problem. Google up some of the other sites besides this one and see what kind of stuff you hear. I'm pretty sure they have good stuff though.
I got my engine from them last year. There was a little bit of machining that needed to be cleaned up, but it really wasnt that bad. Some of the areas of the block that were machined still had some metal shavings stuck to them. It was just sharp pieces that were extended out past the original hole and it took 5 minute to clean it up.