*^*^*Spoilers... Don't read if you haven't seen it*^*^*
Plot 3 of 5: Full of holes. Example: If Megatron can be brought back to life with an all-spark piece, why can't Optimus? If Sam has to "earn" owning the matrix, why can The Fallen just grab it and go.
Effects 4 of 5: Would have been 5 except the non-crucial CGI characters weren't as "polished". Look closely at the animation and polish of the Twins.
Acting 3 of 5: As funny as the script was, you don't "feel" for the characters like you did in the first film. The vulgarity doesn't help.
This being said, I would see it again, own it, and recommend it. As much as it was a 3 of 5, I thoroughly enjoyed it.