Well, I ended up picking up one of these on sale, along with a couple spare packs of belts for it. It's pretty easy to use, as long as you take a few minutes and read the manual first. There is a small learning curve with it, as many have said on a whole bunch of internet reviews. I would recommend practicing with an unimportant knife first in order to get your technique down and to explore the different angles that the device can be set at. I'd also say to not progress to a finer belt too quickly.
My initial impressions of it are that it's a great way for the average guy to achieve very sharp results with a minimum of time invested.
Currently, I still feel that I can do a better job free-handing a fine edge using my $35.00 Harbor Freight 30" belt sander, with Lee Valley belts in different grits and micron ranges, and a good leather strop with black and green compound. Maybe over time and more practice with the Ken Onion I'll be able to achieve the same kind of edges I can make with the HF 30".
All in all, though...the Work Sharp Ken Onion is a solidly made tool that can produce a very keen edge on most any knife, axe, or cutting tool.
If anyone is on the fence about getting one, FWIW, I'd say it's worth the bucks as long as you aren't expecting a mirror edge within 10 minutes. Once all of the nuances and plenty of practice is done, the tool certainly is capable of as keen an edge as any field or kitchen knife would need.