First experience was in 2008. I sent in a white Endura and a Delica Wave to be sharpened. When I got the knives back, both of them had sticky crap all over the handles. I have no idea what it was. So I emailed them and then sent them back. I waited for 2 weeks, emailed them again, and apparently they forgot to ship. I give them credit for 2-day shipping after that, though.
The second time was about 6 months ago. I sent in a Native, ZDP Endura, Delica Wave, and a Caly Jr. SS. I got the goods back 6 weeks later (after I sent an email inquiry.) The Native and Endura came back very sharp. The Delica and Caly Jr. - not so much. And the Caly Jr, although it wasn't in the best of shape when I got it, had blade play in all directions when it came back. It could have been that they cleaned it out and some dirt that had been keeping the play at bay got removed; the blade didn't even have much of a "snap" when closing anymore. Again, I don't know whose fault that one was, but it wasn't that way when I sent it in.
And to answer your other questions: you pay to ship to them, and then include $5 for them to ship back to you. Turnaround time was about 4 weeks the first time and 6 weeks the second.