I've only recently watched it. I attempted to watch it when it originally aired, but couldn't because it was on UPN and I've never gotten that channel in the area where I live. It just isn't on cable or regular television here...which I understand is strange to most people.
Anyway, what I have seen of the show, I really enjoyed. I think the primary reason that people didn't like it was that the crew didn't feel or act like a normal star trek crew. It's kind of unfortunate that most people weren't able to see that this was the point: they were the FIRST star trek crew, having to deal with space travel itself as an unknown (rather than it just introducing them to unknowns) without rules and guidelines like the prime directive to tell them what to do. It made the show unique, which, while I appreciated, I could see how some people might find it distasteful.