GW is not a good company at all. In fact, I would go so far to say they are one of the worst gaming companies out there, much worse than Wizards, White Wolf, etc.
-They don't bother to proofread. They have a virtual monopoly, and have never bothered to proofread. Ever. Want proof? Look at any book they've put out.
-40k (can't speak for other systems) has millions of holes. Millions of rules conflicts exist throughout the game, and players always have to guess, or whatever. They don't want to take the effort to make everything fully integrated, make keywords with set definitions ('modifier', for example), make everything seamless. Why don't they want to? They don't have to, and they know it. Wizards of the Coast has a much harder time with this, because they release two new sets every year, and have to make sure every single card fits in seamlessly with the thousands of other cards they have released previously. This works great, for the most part, and when they do make mistakes, they have a system to fix it. GW messes up, and their system includes making up an FAQ that further adds to the confusion.
-They are price gougers. Although it is their right to raise prices, they're doing so past what I think would be fair.
-The only contact R&D has with the players is releasing the odd article to hype up the release of something new. Wizards, on the other hand, releases several articles every week, answers mail, answers player's questions, and, overall, has a much better contact with it's player base. And it's their legal and moral right to sue Rancoured_Elf, who is, by definition, a theif so anyone who brings that up has merely a moot point.
-They bully shops that carry their product - setting prices, disallowing them to sell seperate bitz, etc. Again, it is their right, however I think this is unfair. I know at least one shop that stopped carrying GW products because of this.
And that's my rant on why GW sucks. I'm sure there's some other reasons, but those are the ones that I could think of.
And to get back off-topic, I like playing 40k, even though the prices are high and the system is full of holes.