Yes I bought the engine in my sig from a guy who had bought it from PAW and them totalled his car within just a few hundred miles.It was totally disassembled when I bought it and I just put it back together and pounded the snot out of it for the last 15 years or so.It finally blew a headgasket or it would still be running strong.
I've bought many parts from them; the only problem I had was a set of their modified small block heads. Valvetrain geometry was off and it ate some pushrods and guide plates. They let me exchange them for some Windsor Jr's - with the extra money of course. I'm sure I'll be buying more from them pretty soon.
Not a fancy "Big Name" that you can drop to impress your friends, but I'll bet more home built engines came out of a PAW catalog than most of us are willing to admit.
If you don't have access to a "A" level machine shop in your area but want to tackle putting together an engine with your own hands - they can offer assistance at several stages of engine component completeness.
I used them years ago, before I got all sophisicated -
... and to be honest, I would not hesitate to recommend them to anyone that has the desire, but not quite all the knowledge. They can provide you with as much as you need to keep from Shooting yourself in the Foot .... Its a good deal and sometime, the luck of the draw will deliver some good factory part number blocks, heads, cranks at junk yard prices - already machined.
As mentioned, they do a pretty good job on the machine work; most of the time they include plastigage and instructions on how to check clerances as you assemble the parts.
All you need is the same amount of skill needed to put a model kit together and you too can be an engine assembler/ mechanic! At least as good as a lot of the people used to assemble "Crate" engines which cost a lot more ...plus you can say - I did it myself.