Bumblebee (helps I care about the characters) DOTM 07 AOE ROTF TLK (They somehow made it sooo boring)
DOTM. My only wish was that we got an actual Megatron fight, but Optimus's battle with Sentinel is so epic in its own right I can forgive its absence.
2007 and ROTF. The other battles went on a little too long for my liking and had excessive human participation IMO.
Based on techninal: DotM>AoE>2007>BB>TLK>RotF>1986 This also includes cinematography, editing, and continuity, which is why expensive renders like TLK and RotF are so low. 2007 should've won the VFX Oscar, but The Golden Compass won for CGI animals, even though those have aged poorly given how animal renders have progressed. Both DotM and Rise of Apes lost to Hugo, which has a great style but isn't nearly as technically advanced. They stopped nominating Transformers at that point because they dislike the narrative of nominating bad films, even though VFX artists are already underappreciated and good VFX should be recognized regardless. Somehow, Suicide Squad won makeup because there are actual edgelords who made that dorky thing popular. Nobody saw Star Trek, which was superior in makeup and overall as a cohesive film. Suicide Squad is worse than any Transformers film in my opinion. Deadshot wanting to see his daughter is about as generic as Cade wanting to see his, but TLK has more technical skill going for it. Based on originality: DotM>1986>2007>RotF>TLK>AoE AoE is a technical marvel, but so many of these final battles have originality. For example, say what you will about the overall quality of TLK, but it's chunks of Cybertron crashing into Earth, and gravity keeps shifting as planes fly between planets or characters fight in free fall. I think that the design for the final battle in RotF is hideous, but it has the Constructicons combine into a dog Devastator and climb up a pyramid, the Fallen orbiting jets and giant rocks around himself, and Optimus going crazy on the Fallen and Megatron with his supermode, so it's quite original. 2007 is as high as it is because, at the time, the battle was groundbreaking and highly original. 1986 has a planet transforming into a giant Transformer with smaller Transformers fighting the many mechanisms inside him; what more do you want? DotM has a giant worm bite into a building and cause it to fall over, NEST soaring through the chaos with squirrel suits, Optimus descend upon the battlefield with a jetback and lead a battle charge on Shockwave, incredible fight choreography for Optimus and Sentinel's duel, fantastic designs that Joss Whedon stole for The Avengers, and a beam in the sky way before other blockbusters overdid that kinda finale. Based on characterization and emotional weight: 1986>DotM>BB>2007>RotF>AoE>TLK This doesn't meant that I think one film is better than another overall. This is just which one hit the most emotional beats. The final battle of 1986 has Unicron lose his patience and level cities under his hand, Shockwave ordering the Decepticons to defend Cybertron, Galvatron wearing the Matrix like a medal because he won't admit that he's a slave, Daniel panicking to save his father and believing that he lost him, Rodimus finally earning the Matrix, the catharsis of vanquishing Unicron, and Rodimus' great final speech. Closely after is DotM, where Optimus and Sentinel's motivations are clear, the reveal that the Autobots survived gets cheers from the audience, tonnes of people actually die to show that the main characters are at risk, the Autobots work their way up killing the Decepticon chain of command, and Optimus finally executes Megatron.
07 is the best. It's the best paced, it keeps the momentum going, and everyone gets the chance to contribute something (even Jazz, who contributes an 86 homage and his own death). DOTM has a LOT to like about its final battle, but I find the pacing to be off. The "final battle" keeps starting and stopping in bursts before things finally take off when Prime arrives to fight Shockwave. AOE doesn't get enough credit for its much more streamlined final battle, which hinges on Hound vs. the Decepticons and the Dinobot Charge. That whole sequence is pretty well edited and executed, and it's not overlong. Then the vortex grinder sequence steps in to ruin the pacing. ROTF is solid, despite suffering from issues that plague the movie overall, and TLK has some cool bits (particularly the very end when it's just the Autobots and Cade/Vivian), but isn't as exciting.
I have a huge soft spot for the Mission City battle, but I gotta be honest, the final battle from Bumblebee stands head and shoulders above not only most of the fights from the other films, but most other fights in Transformers media period. The characters are all using their ability to transform in creative ways in hopes that they'll get the upper hand, Bumblebee gets to demonstrate his tactical aptitude, we get to see the distinct difference in Dropkick and Shatter's fighting styles, we get to see Shatter lose her shit and just wail on Bumblebee when her plan is foiled, Charlie gets to play a believable but still meaningful role in all of this, and perhaps most importantly to me the fight is violent but not something that's lingered on for too long. Dropkick's death is horrifically violent (and something that could only happen to a shapeshifting robot) but rather than cut to slow motion to show him exploding in visceral detail like Bay would do, the camera instead settles for watching his parts scatter across the battlefield, and then Bumblebee and the audience by extension moves on because there's still Shatter to worry about. It manages to be intense and dynamic without resorting to making anyone involved an idiot, and this includes Charlie.