Jazz
because its so ... jazzy

 

I care.

 

Favourites:
First: I wasn't that fond of it at first, but I've come to appreciate Shockwave; I love how when transforming from jet mode, the wings fold down as his torso rotates, while the front of the jet slides back and snaps into the legs. I like how he flips a few times when going into jet mode too.
Second: Quake is pretty awesome. He flips forward, legs lock into place, the turret snaps down and the gun slides out. I cannot state how much I love the gun sliding out. When he transforms, it slides back in, his front makes the legs and stands him up and he's pretty neat.
Third: Optimus. It's great how he just flings himself up, chest slides up, arms tuck and legs fold around. I like to sprint than transform, as if I were running into the conversion. It's pretty neat  


Worst:
Third: Hardshell. It's just too quick for me. I want to see more from it, the shell forming, the legs coming out, the head folding around. But it's just a quick jerk  
Second: Silverbolt. I preferred him in WfC, where he twisted himself around more, but here he just leaps up into it. It's not as intricate or interesting anymore.
First: Honestly, Zeta Prime. Which is a shame because I loved his WfC shifting. But here, he just spins around and he's already trucking. There's no intricate movements like with Soundwave or Optimus, no pieces locking into place like Magnus. He just... spins  

 

Top 3 Autobots:

Scattorshot = Love the sound and I love the animation. Only makes sense when you are using the same legs though as the tank treads appear out of nothingness.

Sideswipe = The sound is just as awesome as it was back in WFC and the animation is even better than it used to be. The flip just looks brilliant when you transform while sprinting.

Zeta Prime = The wheel spin at the end of the animation just makes this what it is, just feels so badass when you're about to speed off from spawning or making a getaway after getting a kill. (That and the sound is pretty neat too.)

Worst 3 Autobots:

Ultra Magnus = Copied sound as Optimus and choppy transformation animation that shows pretty much no parts changing and the back to robot mode one is even worse. Very lazy.

Wheeljack = The transformation animation itself is fantastic, love the sound when going into vehicle mode, sounds like some high performance engines kicking into life as well as the backwards flip back into robot mode.
But... why on EARTH did they give him Jazz's tranformation sound when transforming from his vehicle mode? Was it an error? Were they just lazy and never made a sound for him? (Which is unlikely as in the DLC Trailer he had a unique transforming sound. WTF?).
It doesn't fit him at all and I know it's something small and meaningless but to me it bugs me so much I never use his chest piece despite Wheeljack being my favourite Transformer EVER since I was a kid.
All in all, I was a very sad panda and it lost some love for HMS because of it.

Slug = Ugliest Dinobot + Lazy transformation + Boring sound effect = Immensely lame character. (And I wasn't a fan of the Dinobots being in MP in the first place)

Top 3 Decepticons:

Shockwave = I love how the all the folds, spins and rotating and the slightly slower pace actually lets you see each stage seeing his emotionless eye all the time. Along with the hi-tech sounds it really sells his character.

Demolishor = The turning spin as the tank forms, the multiple cannons emerging as you see all the panels rippling into place really makes this one unique. The rotation really sells this one along with it's low pitch and metallic take on the classic transform sound.

Deadend = Love the natural movements of how the character throws himself into the spin with the kick of his leg as all the spikes and panels flip into place in the same movement.
The rippled sound is badass too.

(Honourable Mention) Barricade = Despite not being in FOC (For some stupid reason) his was probably one of my favourite, the rolling parts formed the vehicle flawlessly and smoothly when he dived forward to the ground, same when he goes back to Robot Mode.
And that sound... so good with a pair of headphones on.

Worst 3 Decepticons:

Quake = Boring character with a boring tank mode with a boring animation and boring sound.
Boring.

Vortex = As much as I love his Copter mode, the animation is a bit sudden. It just looks like his robot model just instantly changing into the vehicle's model. Sounds a kinda neat though.

Hardshell = This was a bit of a stretch, but his animation is a bit choppy and just looks like Brawl's re-purposed. Sound is awesome though.

Yeah, I love the transformations of Fall of Cybertron.

 

I don't really remember anyone directly talking about how it works... Similar stuff, though...

Have you seen the FOC one? They utterly ruined it. He just falls over and then a car does a U-Turn. And they still had the balls to keep his WFC sound effect.

EDIT: Updated.

 

I cannot tell what's going on with most of them. The robot does some twist/dance move/lurch, geometric chunks of metal flip around, and a vehicle somehow condenses out of nowhere. The few I can make some note of:

Warpath - I can actually see how that transformation works. It's simple and cheats like all the others, but at least it makes sense.

Perceptor - He rips off his cannon and goes to impales himself while a tank envelopes him. So absurd it's hilarious.

Grimlock - Cheats the worst of them. The arms-to-legs makes enough sense, but the rest of the T. rex just pop out of nowhere. No wonder Campaign mode always had that special cinematic play every time you transform as him.

 

Actually, his legs robot legs turn into the tail. At least in the campaign...