3rd party art
I won't go so far as to say I think all 3rd party art is fabulous (or even exceptionally good for that matter), but most 3rd party publishers seem to be hiring previously 'undiscovered talent', and some of that talent is at least as good as the 'established talent'.
This is the pitfall of using unestablished talent, you must wade through hundreds of people who's mother told them they were great before you find someone who's mother was right. *chuckles*
I have to give Dark Quest serious kudos for doing everything they can to make every book as good as it can be. I know that both Gillian (DQG's delightful AD, and regular DQG artist) and myself push ourselves as hard as we can to give Tensen the best art possible to go with those books. Heck, I'm taking a break at this very moment from the 3rd final draft of an illo. for Enchanters before I start the 3rd final draft for another.
And as Tensen pointed out (as have many others, on many occasions), people's tastes vary widely, which is both blessing and bane.
The really hard part is to take a good look at an illo. done in a style you dislike, and try to see where the technique itself is solid. I don't like the style of the Elements of Magic cover (and 4CTF), but stylistic preference aside they are well-done illos, and stand strongly. The proportions are good, the stances, posing, and positioning are good, and within the artist's own style, everything is pretty much dead-on. They have a nice internal consistency.
I guess the basic point is, yes there's a lo of garbage being put out, but there's some fabulous 'uncut gems', too. I think it's a good trade-off (but then again, it's gotten me published, hehe).