I've played with the Holley 94s and have had good luck with them. There's a site called webrodder.com that has some good artilces on them and the rochesters.
The 97's are getting hard to find and many are in pretty rough shape. They require a couple of special tools to build that can be hard to find. They were used as OEM only on early flatheads them later were aftermarket replacements, sold for about 10 bucks a pop so lots of rodders bought them.
There are supposed to be some new ones coming from England, but nobody's got them. They look great but I'm told they will run over $500 each by the time they are in production. Used 97's will cost you around $400-450 each to get decent carbs. 94's can be had for a little less and are generally a better carb.
I've tried Vintage Speed as have several others and we've ALL had nightmares with the guy. Crappy work and it takes forever to get anything back. None of us have ever been able to make a set work right from him and I ended up sending mine out to Jere Jobe to get them fixed. Wrong parts, not cleaned right, not set up right. Hate to bad-mouth but this guy is really BAD.