I have seen and enjoyed Michael Apted's 63 UP.
Despite not seeing it through official channels, I did not get a ticket through the press office or PR handling the film, and so not technically bound by the request to hold reviews until the film hits theaters next month I am holding off. (I have had too much grief from different PR people with my reviewing films I saw on my dime who insist simply that because I am press that means I have to abide by any rule they set)
I will say it is a wonderful continuation of the series and if you like the previous films then you should very much see this film as well. Also if you haven't, this is a great place to jump in.