Okay so I opened the toy up and transformed him. Here's my thoughts:
I don't think Megatron has a good of a Presence as the Leader one would (if I had it). His size is the same height as Starscream about and Rachet stands taller than Megs.

I really don't like the ice fragments on him. I wish it was made as a post-freeze state where he was actually mobile. If I recall the ice was all melted off when he escaped Sector 7. Definitely the ice was not a good thing for Hasbro to include.
Also the ice seems to be made from softer plastic unlike the rest of the toy.
The face paint job is really shoddy. It's a black-ish look and his glowy eyes are blue. Desperate need of a repaint.
The feet don't stay flat. If you set him on a tabletop he'll stand on his feet fine, but when you pick him up the feet spring and retract back as if going back into vehicle mode and I thought that was not a great feature.
Stands well.
Arms are a bit flimsy. the hands are a big f&**ed up in that there are like 3 fingers per hand and they are amber colored. Again, the whole paint scheme thing is just goofy.
I would say that with a paint custom the Leader one would be best. The presence of this figure doesn't stand out as much as the other Yoyager series. And it definitely looks awful next to the great Leader Prime (which I will be doing a custom paint on). Leader Prime needs Leader Megs for sure. haha!
I know the sizes of the toys have never truly been to scale with each other, but you'd think they'd take some consideration of size in the Voyagers to make megs at least as tall as Rachet. I just thought that was a bit odd.
Voyager doesn't place high ranks on my movie TFs list, but it's a good addition to my collection as a movie toy completionist.