TWOK - Had it all, space battles, sacrifice, family issues, revenge, and overall plot.
TSFS - Visually stunning for when it was made, nice continuation of TWOK. A little confused that they needed to go to Genesis in the first place. I thought they coulda just went to Vulcan and transferred Spock's Katra to its final resting place. They were not aware of Spock being alive until they reached Genesis orbit. However they needed a reason to get Spock alive again and they did a pretty good job. A lot of flaws don't become obvious except under repeated viewing and the only reason to do that is because you like the movie enough in the first place. To make my point the vast majority of movies I have seen I have only seen once. (example - Practical Magic - 1, Forrest Gump - 100)
TUC - Wasn't sure where to put this, the cold war timed theme seems dated, also why would the Klingons die without Federation help? Surely they have an empire with some more planets and a fleet to move people. These just needed an Non Aggression pact with the Federation which shouldn't have been to hard since they were not at war anyway. The plot devices invented to tell the later story of Kirk/McCoy's arrest were thin. However it is still a solid movie.
TMP - Slow paced, tried replicating the massiveness of Star Wars, takes a special place for being one of the two original six movies to depict the Enterprise with a full complement of trained crew members.
TVH - Good movie but would rather see Star Trek in space.
TFF - Tons on potential, I give Bill Shatner the benefit of the doubt that it was rushed to point where it caused the quality to suffer. A quest for God/Heaven? Not sure if this is the purpose of Trek but they gave it whirl.
Its hard to rank a series of movies you love especially when everyone has there own take on them. My level of enjoyment in watching the worst or the best is surprisingly close. I love them all and would rather have them in their flawed glory than not have them at all.