Motion Picture: F
Horrible pacing, plodding, drawn-out...everything. It's a lullaby, not a film.
Wrath of Khan: D-
Better than TMP, tho that's not saying much. A lame villain, boring battles, gratuitous violence to the point of just being silly, tho it did have a couple of good moments
Search for Spock: Can't Comment
Voyage Home: B+
The premise is completely ridiculous, but it's a really fun romp, and a good time from start to finish.
Final Frontier: Can't Comment
Undiscovered Country: A
A great movie to send off TOS. Tons of great character moments, an interesting plot, some cool ship-to-ship stuff, and Sulu's USS Excelsior teacup was awesome.
Not bad, not amazing. Flawed, but it has more good than bad I think and it's still fun to watch.
First Contact: A+
Debut of the Ent-E, the new uniforms, and one of the coolest space battles in the franchise. I think the Picard/Revenge thread was handled really well, and the atmosphere was amazing. The Borg Queen is the one "Dammit, it was almost perfect" of the movie. I didn't mind her too much, since I think her role in the movie was played well, but the Borg WERE scarier with no one voice.
The main story just feels lame, dull, and plodding. Character interactions are mainly what save it.
I'll concede that it was pretty flawed (pretty much everything about Shinzon and the Scimitar for example), but I think it's a VERY fun movie to watch and leaps and bounds better than TWOK. More great character moments, a great OST, and just a good one to sit and watch on a bored day, I find.