I researched the subject several years ago. At that time I found that the prices were way too high. At the same time I learned that the quality was no better than connecting two good machines and dubbing that way. It just wasn't worth it to me.
Is there a reason you want to transfer vhs to vhs instead of DVD? The quality is much better and the prices are much more reasonable these days.
All I can say is we've had a Go Video dual deck VCR for many years and it has served us well. Have copied many tapes with it.
We recently purchased a DVD/VHS player/recorder that allows us to tape from tv to DVD or VHS, tape DVD to VHS and VHS to DVD. We didn't get rid of the Go Video machine, we just moved it to a different room/tv.