CGI is a mixed bag Lord of the rings used good CGI and looked good but I feel George went to extremes for the SE and the Prequels for eg I like the Yoda(fan of) The Kamonians etc in the P.T but some of it looked cartoony eg Two Headed the racer announcer the guy with the big head an no body Jar Jar Geonesions etc and some of the scenes looked like a video game level eg The droid factory in clones. and as you can do anything with CGI i feel Lucas sometimes crossed the line of believeablity even for Star Wars in the prequels

You cant the beat the gritty feel of natural locations still rather complete greenscreen work it look to polished, clean and sometime unatural at times and the actors prefer working in locations rather than screen work.

the same with SE the X Wings taking off from Yavin look cool and I prefer that to the 77 version and the re-done battle sequence I like(though maybe very slightly less than the models not sure) but Jabba looks like a cartoon and nothing like the ROTJ puppet as does the new musical number in ROTJ, you can tell in 70s and 80s film what is a CGI additon and what is not.