As I said, Jumpstarters (and Battlechargers) are easy one-step transformation Transformers in theory. I'd put Gravity Bots in this same category. In reality these Transformers are often trickier because their gimmicks are prone to mucking up or just breaking down. Actually, the Battlechargers' transformation gimmick tends to still work well even after 23 years, but the problem is that their back supports become floppy in robot mode.

Quote Originally Posted by Lordy
Easiest? Probably one of the Throttlebots
You know that the Throttlebots all follow the same transformation pattern, right? Having said that, Wideload would be the easiest to transform since his arms don't clip onto the main motor section; you can lift up the body without having to fold the arms out first. Doesn't really make much of a huge difference, just gives you a slight luxury of folding the arms out later if you want. But the Throttlebots aren't one-step Transformers, they're actually four-steps. I can't think of any Transformers that are easier to transform that one-steppers.

Quote Originally Posted by 1AZRAEL1
Agreed, he was a pain, I transformed him once, took me 1 1/2 hours, then back to robot mode. He will stay that way the rest of his life.
Same! I agree with what Lint said about his transformation being rather counter-intuitive, but I don't find the gun mode worth all that effort. I keep my MP Megatron in robot mode and my e-Hobby Megaplex in gun mode, which is closer to a 1:1 scale anyway.

Quote Originally Posted by 1AZRAEL1
MP Grim is hard as well, I haven't even tried. My bro-in-law did, but he will stay robot mode as well.
MP Grimlock's not that hard*. Half the toy pretty much transforms like 1985 G1 Grimlock but the other half transforms like a Masterpiece.

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*I'm not saying he's easy either! Like I said, half of the toy still transforms like an MP, so he's still no walk in the park, but he's relatively less complicated than other MPs.