I would characterize myself as being an overall fan of Wishbass. Wishbasses sound amazing, and they look really great, and they do feel great IMO, though they feel unlike a standard bass guitar and more like a cross between an UB and a bass guitar. Wish is also a really nice guy, and he has managed to find the balance between artist, populist, and capatalist.
I have 3 wishes. I bought a 4 string Sam design in September, with a body made of about 12 different woods.
Last month I bought a Peanut (4 string) design made out of Spaulted Maple. Somehow FedEx routed the package from NJ to Southern California, so it still hasn't made it to my NYC apartment, but I should have it Tuesday.
Finally, I have a Wish fretless 7-string (B-F) Peanut which I just got last week. It feels more like a conventional bass than the Sam in that it has a thin neck with a truss Rod. A very sweet bass, and I plan on posting a full review on it in time.
Everything everyone has said about the woodwork is pretty accurate. Wishes are a bit rough around the edges, and certain things may just drive you nuts about this. For example, he uses tack nails as dot markers on the neck, there are the occaisional gaps at spots between the fretboards and the necks, etc. I recently sent my Sam back as one of the joints between 2 different body woods separated! As bad as that is (there probably was not enough glue in the joint) Wish is making good by it (fixing it and covering the return shipping).
Having said all that, I cannot emphasise how good these basses sound. I am not a bass snob, but I do own some high end basses (a Fodera, a MM, etc.) and the Sam Wish is among my favorites. Really woody and organic sounding and fun to play. In fact I have had more compliments on the wish than on any other bass I have ever owned. It DOES perform. I think I should have stopped at 2 Wishes, but I went a little crazy because I really do see them as something so incredibly unique and functional for so little money, and who knows how long Wish will keep making them. They are to me, kind of like playable sculptures. As I mentioned in another wishbass thread, my attitude in buying the first one having never played one was "Hey, if this is a good bass, then great. And if not, I can hang it on my wall as art." Only time will tell if they last without truss rods, etc. but I am enjoying them for now.
To echo what others have said, you are buying something very different when you buy a wishbass. If you are looking for a conventional bass, there are plenty of solid $300 values that are better choices. But for a handmade, hardwood instrument, with lots of character and good looks, you can't beat a wish. If you wouldn't miss the $300 or so, I say give it a shot. You can always sell it on ebay, where folks buy them and then actually sell them again for a little bit more than they paid.
Good luck to you.
