Nobody here really wants to talk badly about the people who built their cars, especially if they still need the connection for customer service or support. Many of those initial relationships transcend the purchase, and can last a very, very long time.
Many of us count our builders as personal friends also (regardless of whose car you're buying, you're going to develop a similar relationship), and Speedster folks just aren't likely to throw a legitimate builder under the bus for any reason -- but this is business, and you're about to spend some money.
Since I had a hand in making my car, I feel like I can say comfortably that the more customized your car is, the more it will need to be sorted out after you buy it. Since you seem to be in the 'used' market, I'd say you're probably looking at two cars which have been sorted out already.
If you can, take your mechanic with you to have a look at each.
Since I don't have a dog in the fight, I'll say guys in California seem to have better luck with initial sorting and teething problems in JPS cars than folks out here in the east do, and Vintage owners have great luck wherever they live.
Wiring in the JPS cars I've wrenched on has presented neatly, but hasn't always worked well. It has been easy to fix, and the wiring has been easy to get to. The Vintage cars have had harnesses which do what they're advertised to do from the first day.
Fit hasn't been the same from one to the next in JPS cars, either. Different from finish, it seems the JPS assembly cuts the invisible corners. The VW half of the car is what it is, and the box tube part is brilliant. The pans are terrific, the shifting linkage clicks and the mechanical parts are much, much better than I could do myself. JPS has absolutely got four-wheel discs figured out, but seems to have difficulty with smaller mechanical bits.
By way of comparison, Vintage is relatively simple in their approach -- and theIr cars reflect that. They're reliable out of the chute, seems like, and mostly Vee Dub. I haven't ever worked on a Vintage; every one I've seen has been running already.
JPS used to use materials I wouldn't use for engine tins and splash protection under the car, but only for aesthetic reasons -- and most likely to keep fabrication costs down. I wouldn't presume to say whether or not that's the case now, but the examples which made it out our way had some wood-textured aluminum siding inside the engine compartment. Easy enough to replace, and not a big deal. Functionally, it works just fine.
All that out of the way, I really like the finish on a JPS. They aren't IM, but they're not far off from something you'd think you would see parked indoors at a look-but-don't-touch car show. The color options on a JPS seem to flow together like you'd want them to, and I wouldn't ever get tired of looking at the examples I've seen.
Once you get past the teething issues, a JPS could be a good choice. If you want to get in and drive to the moon and back, maybe at the expense of having a VW chassis, there's absolutely nothing wrong with a VS.
You're certainly better off to ask the person who owns one, as they used to say, and attending one of these crazy get-togethers is the best way to go.
Or, have a pre-purchase inspection done by someone who lives close to where the cars are that you're interested in. If one of them is in the Baltimore area, for example, I'd be happy to go and have a look for you. Many others here would do the same. It's certainly possible we're already familiar with the car you're looking at.
Good luck with your decision!
