Thanks for the responses everyone. I've commissioned a bit in the past, and 97% of it has been good. I did have one artist who would send watermarked, low-res photos before payment. He sent a page that was a bit different than what I scripted. I very kindly asked a fairly simple change based upon the original scripting and never heard back from him, so the comic remains unfinished. Oh well.
I also generally like to work with artists who work specifically with TF and other process related themes, though right now I'm planning something with an artist I've worked with in the past who doesn't necessarily specialized in TF.
What I'd really like is to find an artist who does high quality manga TF commissions, much like nojo, but it seems that nojo has left the community.