Tim, I use 'Harmony Assistant' software (a kind of junior Sibelius) to write my guitar and mandolin arangements. I do it manually, using the laptop trackpad. It was a slow process at first as I had to get to grips with the software, but I can get by at a reasonable pace these days.

One of the things that Harmony Assistant can do is to read midi files and present them as scores. What's immediately apparent, as Stu has pointed out above is that the quantization can produce scores with infinitesimal note and rest values from bar to bar - incredibly complicated and laborious to knock into readable shape.

Better by hand, I think...