Well, in a way it basically mirrored the classic scene from T2 with Arnold trying to smile (which may have been a deleted scene, or from an extended cut, but still present). Overall I wouldn't say the movie was overly comical though. The smile was a recurring gag and the middle section had a small portion that provided a few laughs, but the main chunk of the movie is serious. It's probably a bit more comical than something like T2 (which also had those moments), but it doesn't go all out on the silly side either.
Definitely better than T3 and Salvation, but not as good as T1 or T2. It's pretty much the definition of a 3/5 movie, something you enjoy at the cinema but nothing that we will talk about 5 years from now.