It's pretty great throughout. Haven't watched the last season and like any show that has been on that long there are some dips (I personally find season 10 pretty bad), but it is amazing how they've managed to keep up the quality. The schemes are always fun (the train smuggling is still my favourite) and the ebb and flow and changing of dynamics between all the characters is really the most interesting part.
I didn't get into it until after it had been on for a few years. There was a period after it started airing that it seemed like everyone in Canada was obsessed with it and I had to be contrarian. I also figured it would just be stoner humour, which I can only usually tolerate in small doses.