I have a decent VHS player with S-Video out. I used one of those cheap USB connectors and it worked reasonably well.
A few years later I wanted to convert VHS-C tapes. The USB connector was broken, and I needed to buy a VHS-C adapter so that it would play in my VCR. Instead of making those two purchases I sent the tapes to ScanCafe. The quality was no different really.
The quality of the tapes I was converting was between ok and downright bad, so that is what I got when they were digitized.