We used to use a solvent decaff which we found left it with a realy sharp tang on the pallete, and left the impression of something just missing. And unfortunatly our customers noticed that too. Last year we switched to swiss water, becuase of the gentler and more natural process of decafination under the reccomendation of our roaster. We trialed a single estate Java and a single estate Sumatra both were a huge improvement, with a much better and fuller taste. The unanimous vote we got was to go for the Sumatra, its smoother taste was a real winner.
I can't speak for everyone, but our customers could tell the difference between solvent and Swiss mountain water.
We started roasting the Sterling Series decafs from Cafe Imports, Mountain Water Process. They roast a little easier than the Swiss Water and we found that the flavor is still there. This is from their web site:
"Quality beans produce a superb decaf -
Café Imports uses only top-grade
beans to make Sterling Series Green
Coffee. Our hand-selected beans are
gently decaffeinated using mountain
water processing. So full of flavor and
aroma, the Sterling Series erases the
line between regular and decaf. "
I can't take caffeine after about 3PM so sometimes I will drink a cup of decaf, and if I didn't know it was decaf I wouldn't be able to tell.