It looks like this topic is actually resting peacefully, but someone pointed it out to me and I thought I might make a couple of contributions from angles that don't seem to have been covered yet: reviews editor and non-game publishing marketeer.
I'm the gaming editor for Black Gate magazine (the fantasy magazine that MThibault reviews for, actually) and there are a number of considerations that I deal with on that level that don't seem to come up in the broader reviews boards. MThibault touched on one of them - space. Black Gate is a print magazine and our average review is only about 600 words. Reviewing on the web is luxury - you can ramble as much as you want (I know, I used to do reviews for SFSite.com). At 600 words, a review has to be really tight - get in, do the set-up, say your piece, and get out. Not easy, but it means that everything has to count.
As MThibault pointed out, Black Gate readers aren't all hardcore gamers and the reviews we carry have to have some appeal for them as well - hence, I ask reviewers to keep discussion of mechanics to a limit and sometimes to elaborate on essential terms that non-gamers might not understand. Carrying that argument back to its source, we're not just reviewing product, we're delivering product ourselves - people are paying for Black Gate and I want to make sure they get something good (even if the primary focus of Black Gate is fantasy fiction, the gaming material is still an important part of the content). I've got a goal of putting out good, readable reviews that make people want to read more reviews, pick up the products, or maybe even get a little more into gaming as a whole. I've also got a responsibility to keep up good relations with the publishers who supply us with review material - I think most publishers realize that a publication with limited space can't review everything and one with a quarterly schedule isn't going to get word out fast, but I hope that they'll recognize the quality of reviews that go out with Black Gate and keep coming back to us.
OTOH (switching soapboxes), I can also understand the publishers' point of view when it comes to dealing with reviewers - I work in marketing for a major Canadian scholarly press and for a while was actually responsible for sending out our review copies. I knew who was requesting reviews and who was producing, and boy, did it steam me when people who never covered anything sent in whacking great lists of requests. Or when people covered something by producing a "review" that was essentially just a description of the book - hello, that's on our website already. It's on the book. If I was a game publisher, I'd be annoyed everytime I saw a review that essentially duplicated the table of contents from a book or said "this book contains 35 new feats and 15 new prestige classes" (of course, some publisher's marketing copy does that as well, but that's another goat). But that's a chance you take when you send out a review copy - maybe it won't get reviewed and if it does, there's every chance the reviewer will trash it hard. The best I could do was keep an eye on things and if a publication or reviewer wasn't keeping up at least a minimal level of return or quality, I'd cut them off.
Still, review copies are one of the most economical forms of promotion going. There's not a lot of extra time and expense involved, the cost to the company is minimal, and the impact is good. Compare a review to an ad - people tend to skip ads more readily while a review (especially a well written review!) will get attention. Sending a review copy costs you postage, the production cost of the book, and a bit of staff time to process. Placing an ad in the same venue costs design, art costs, space costs, and again a bit staff time - with the trade-off being that you're paying for a guaranteed appearance and whatever message you care to run. For the price of one ad, you can send out a good number of review copies and if only two or three of those get reviewed, the number of people who are hearing about your book jumps dramatically (and that's not counting any word of mouth spread by the reviewer directly).
When and how a publisher can use a review depends on what part of the publisher you're talking about. Editorially, a review at any point after publication can give you feedback that you can plow into future prodcut development (although reading reviews is a lot like getting a book critiqued in the draft stages - if one person complains about something, it could be nothing, but if multiple people complain about the same thing, you should start listening). Marketing and saleswise, of course, reviews are best fresh: as a source of blurbs that can assist in other marketing (one of my measures of a good review is that is says something potentially quotable about a product) or that can drive up early sales. Even slightly older reviews are good though - blurbs are still good for reprints or sequels and backlists sales are nothing to sneeze at.
So what does all this mean to the topic? I guess I'd say that for reviewers, it means try and write for both parts of your audience (consumers and producers); for publishers... well, you sends your books and you takes your chances - wherever the cow chips fall, you can still scoop them up and through them on the pile.
From either side, getting a really good review out is still tremendously satisfying.
Don
(Gaming Editor, Black Gate -
www.blackgate.com)
C'mon guys, it IS a factor. Not the only factor, but a factor. 
I don't bother putting price per page anymore, but I do maintain a database so I know who lies about where on the value scale, and will usually comment if a product is particularly pricey or cheap for the page count.
