I'm not a regular watcher, but I have seen a number of episodes. It actually isn't offensive, imo...it's emphasized quite a bit that the main character is pretty much living in complete and constant misery.

I think it suffers mostly from cheaper production values...what it is on, USA? The writing is sometimes silly, though some of the crimes they come up with are quite clever. Also, it seemed to get a bit better production-wise later on, though I can say that for certain. I think it just doesn't have that "slick" look like L & O.

I think some people complain that Monk, the main character, isn't a convincing OCD case. I think that's a bit of a judgement call...they play up his compulsions more than his obsessions, but well, compulsions make for better television. And they do use his compulsions for humour, but in a pretty gentle way...they take the OCD issues serious enough.