Let me just say that what Crothian does is nothing short of remarkable. Amazing, really. Publishers should really what he does it an awful lot of work, for basically little reward.
At least in my experience, PDF reviewing is very tricky, because you have to spend tons of time at the computer - both for reading the product, and writing the review. Print stuff, you can at least read in bed or while sunbathing or at least, not being glued to a screen. (Even if he has a laptop, it's still quite a lot of computer time)
(No real point to this posting, other than y'all should really apreciate him. I've been working on some PDF reviews I somewhat foolishly agreed to do, and I'm quite late on them because these days I spend most of the day outside, enjoying the summer, and when I'm in with the computer, I'd rather either browse the net or play a computer game. Thus my admiration for Crothian. I don't think most people realize quite how much effort is involved.)