The episode is actually quite good, but I don't see the point in bringing back Richard... I mean, Monica had such a hard time getting over him, and bringing him back was just not neccesary, but I guess they needed a story for Monica...
Anyway, we get to see more jealousy on Ross's part, which will grow to something much more bigger in a few episodes.
I really enjoyed the Rachel/Joey plot, it was really interesting seeing how they commented on the books they were reading, and at the same time, I was surprised by the fact that Joey likes reading books.
Phoebe's story was also quite good, but it just wasn't so good to make the episode above average. But we all know that the writers can't keep on writing amazing episodes. I like this episode just as much as the other episodes.