My father and I bought a 5-speed from American Powertrain for dad's '72 Big Block Chevelle SS and the experience was very positive. We went with a TKO600 ProFit kit and one of their hydraulic systems. Customer service was great, product was as promised and we were even invited to their shop to do the installation on their lift. That made it a pretty easy job.
Much later, when my father (old timer that he is) decided he couldn't get used to the feel of the hydraulics and wanted to swap to his old mechanical linkage (as I said, he goes way back) Gray, one of the owners, came in on a Saturday to spend the morning helping me get it swapped back over. He even pulled a couple of parts off the shelf that were needed and handed them to me.
Now don't expect them to do this for everyone, but I think that is pretty much an over the top effort from where I stand.
Dad loves the gearbox, the car cruises great with it and I would recommend them to anyone.