I had my Nikon D70 converted by maxmax, with mixed feelings. Despite their making a big deal about their clean room techniques, my camera came back with many large gobs of gunk visible in every photo that I was unable to clean off myself with a bulb blower or a Visible Dust brush, so I sent it back to them for cleaning (which they weren't particularly helpful or gracious about), but it did come back clean the second time.
Since the conversion, I've let the camera auto-focus, and sometimes it works fine and sometimes it doesn't work quite as well as I would like (with somewhat soft images). In the future, I'll probably try to manually focus instead.
I've found that I have to be careful to not overexpose - simply using the camera's luminance histogram isn't good enough, since the primary channel with signal, red, can be badly clipped while the other two channels are pretty dark. Oh, for a triple RGB histogram! So I typically take several bracketed shots, from about -1 to -3 stops on the exposure compensation, and one of them is usually good.
You have a lot of options for post-processing, and the images need a lot of post-processing because the red channel is the dominant one. You can adjust levels on the various channels to bring them more in line with each other and then switch some for weird color effects, or purists can just take the red channel and turn it into B&W (which is what I usually do).
If you want some examples (after post-processing), here are links to some of mine:
IR image 1IR image 2IR image 3Lisa