Considering series 6 was the weakest this series was a good way to make up for that. It's truly awesome and epic episodes like Paper War are just too good to miss.
Series 7 was supposedly meant to be the last series. I don't believe that was really the case for a moment. It was left too open. Whether they meant it would be the last for a few years or something it would have been criminal to leave it open like that even if Bellisario left Quantum Leap's ending wide open (though I think that wasn't meant to be that way either).
Do the right thing and get all 8 series. If you are happening to just buying series 7 then at least get 8 as well so you can complete the Limbo episode.