I hadn't really seen anything about the show before, so I went in blind when I started watching it on Netflix. To my surprise, it was amazing. I loved the characters, especially 'Nathan Young', he was incredibly funny, albeit annoying at times. The rest of the cast had great chemistry, but somewhere along the lines, it just fell apart.
I watched season 1-3, and a few episodes of season 4. But season 4 just ruined everything that I loved about the show. Practically every original character was gone, and I had really grown fond of them, so to see the new faces get introduced killed the vibe.
In my opinion you don't need to see season 4 or 5, as season 3 ended quite good. Horrible, but in a great way, going full circle with everything.
If you want to watch something entertaining, then Misfits is probably for you.