I've sent them out for a long time. I used to use a Makita wetstone grinder (the horizontal jobby with a long knife jig) but I found that the longer the blade gets the more work it us to get an edge on (and even with a jig it still wasn't straight all the time , 12in was the absolute max.). Still hone them myself when they come back from the sharpening service, though.
I have to say I'm keen on the idea of disposables, partly because they set-up so quickly, but I don't like the price of conversions (I did try one a couple of years back) and the cost of the disposable blades is prohibitive
IMO. The advantage is quickly lost when you get a fast-set magnetic setting jig such as the Panhans.