I don't understand why so few people rate him. His link up play is pretty good (good enough, at any rate) he's good in the air, is a good finisher... He's not the worldclass striker (yet, at least) that everyone thinks Arsenal needs, but maybe that's good. Really good players tend to get overly ambitious; Giroud is good enough where he beneficial but not so that any club would want to snatch him. He'll get 20+ goals next season, mark my words, and that's quite a solid return.
Also, do you really think he's been Arsenal's worst striker, considering who they've had up top?