I'm a bigger DC fan than Marvel and GL is, after Supes & Bats, my favorite DC character. I like Ryan Reynolds and think he's very talented as a comedian and even actor.
I'm not a fan of Blake Lively but I think she did a tolerable job although not being anything how I'd picture Carol.
But the movie was so horribly flawed that I can't fool myself into liking it.
Parralax looked like poopy. Literally - big brown and yellow strands of...well, you get the idea. The headline could have read - "Coast City goes down the toilet!" and it would have been accurate. The big face and the tendrils and everything was very, very weak. I did like what they did with his backstory - being a former Guardian makes sense. But there was too much exposition - Parralax could have been saved for the sequel and let it all be about Hal finding his Will and battling Hector and perhaps at the end we discover it was Parralax infecting Hector.
In fact the end with Sinestro is totally and completely unmotivated and seems like a gratuitous nod to fanboys more than anything else. If in the second movie parralax had done something that hit Sinestro personally and it was his own failure of will that caused it - he would have a reason to turn to the easier power of fear. But to have him just appear in the suit - bah. Contrast that with the more logical and better handled Magneto in a classic suit at the end of X-Men:FC.
Sinestro had just welcomed Hal to the Corp and praised him - he's a long way from the ____ retentive Sinestro that needs the fear ring. But Strong did a good job with what he was given. Hal's character was also believable -and not really ******-y as some reviews have complained. I couldn't get over how unattractive Blake Lively is (to me), so I really couldn't care less about her character and there really wasn't anything in her performance that changed my mind. Although I couldn't point to anything she did particularly wrong.
Saarsagard was great, but I'd agree with the above review that said he finished in the same place he started - no character arc at all.
The art direction was okay - I'm still not a huge fan of Hal's suit, but I think it worked on Sinestro and even Abin Sur. OA looked great, as did the Guardians - too bad about Crapalax.
As a DC fan it's a bit disheartening that Thor and especially X-Men:FC were so far superior films than GL. Despite Nolan's Batman I think this is a huge setback for DC films in general and used up a lot of good will the movie going public might have for DC characters. If they even make the distinction at all.