The general reception is 65% on Rotten Tomatoes and 55% on Metacritic from the audiences. I think it's rather the usual band of nerdculture hihi praising non-ST fans that give this movie a pass.
In this day and age, everything that's really, really popular (and there's nothing more popular than SW tbh) tends to have a polarized reception. That's not surprising. TFA will have a better reception because they played safe. I find really funny than when they tried to do something different, everyone was like: "THIS IS NOT STAR WARS". And when TFA came: "THIS IS JUST A REHASHED EPISODE IV". What I mean is that it's impossible to please everyone. I loved the movie, and I can assure you I'm a huge SW fan. And I wanted exactly what they did. A shake up in the franchise model. Something different but great.