We've got 'em on the buggy, but haven't been able to put many miles on them yet. (stupid broken tranny)
I've read threads elsewhere where people are bagging on them, saying the shafts bend and seals blow. I take most of those with a grain of salt, since the seals are basically the same as any other you'd find, including those in hydraulic rams and other brands of coilovers. A typical "rebuild" of ANY shock of this type includes new seals, since it's a "wear" part.
Shafts bending I can't really see happening unless there are side loads on them somehow---and that means binding, or impact. The Doetsch have a 3/4" diameter shaft, compared with 7/8" on a SAW, but I still can't see them folding due to the column load alone.
Trust me though, I'll post up if I ever do have any problems with 'em.
As to why they're cheaper....I can't answer that for sure. Part of it is probably how they work their marketing--they don't build the shock until it's ordered and paid for. They don't have to produce them in advance and sit on inventory. That's good for cost, but bad for availability--where you (and I) can buy a SAW shock off-the-shelf and have it within a couple of days, it'll take some time to get the Doetsch ones.