The series as a whole generally get's rated lower than the Halloween and Nightmare series' by most people. Personally, I thought alot of the Friday movies were actually enjoyable to watch. (Even the one's most people couldn't stand). I'll agree with you on Jason takes Manhattan. It's very fun and enjoyable to watch and although it is not ranked very highly as a movie, I finished the movie in one sitting and it actually had me hooked a few times.

The only Friday movie I really didn't care for was Jason X. The rest I liked. If I had to make a top 5:

1) Friday the 13th: Part 3
2) Jason goes to Hell
3) Friday the 13th Original
4) Friday the 13th Part 2
5) Friday the 13th The Final Chapter