No shocks, no disappointments. It's a classic family cartoon (made with CGI) with good guys, bad guys, a vaguely Hudsucker Proxy meets Wizard of Oz plot and the requisite postmodern asides, even for the kids ('yes we know you know it's a surreal cartoon' etc.).
There's plenty of invention in translating human attributes across to machines but that's where the invention ends. The film is purely a vehicle for its star voiceovers and CGI wizardry. For the latter, a laurel or two although I wasn't quite so ready to buy into the voicework: Robin Williams especially has a tendency to modulate the volume of his projection so wildly as to render many lines inaudible (sic an actor error, not production). One for the under 12s while you do the tax return. 4/10