The two best combiner teams from Generation One were the Protectobots and the Terrorcons.
This has absolutely nothing to do with which two teams I owned as a child.
(yes it does)
But do you know why the Terrorcons were the best? Because they were effin' monsters. Vehicles are essentially little boxes, but a monster has arms, legs, teeth... all these extra things to play with. Terrorcons, then, transform into two separate things you can do things with (besides scoot along on the floor). So, yeah. They're empirically the best.
(i had them when i was a kid)
And now there's a new combining version of them! I've talked about Hun-Gurrr, the torso before, and I got Rippersnapper a few months ago, but since then I've gotten his other three limbs. I'll say right off the bat what makes these toys improvements over the originals: they have working jaws. Other than Blot, they all have working jaws. It's by far the best improvement of the entire set. Like, sure, the articulation is way up all around, but frankly jaws are the most important.
(Blot's jaw does seem to be a different piece versus the plastic that makes up the top of his head, but there do not appear to be any joints to allow the jaw to move independently.)
Cutthroat is the weakest of the limbs. Engineering-wise, he's large amounts of the Dinobot Swoop repurposed. He's got the same thighs, arms, and he mostly transforms the same. The only difference is how the beast mode feet get tucked away. But his beast mode head is hinged pretty loosely, and so it likes to fall off. The beast mode torso doesn't hide very well that it's just a compacted robot mode, and so it looks elongated and goofy.
Blot, other than his lack of chompers, is by far the best, though! He wads up his robot mode legs behind him in beast mode to create a different shape entirely, resulting in this angry grumpy cube. I dub him "Most Improved" of the new Terrorcons, since he's just better in all respects. He doesn't just stand up and hide his monster arms behind him. The monster torso/head folds back, giving him a different robot mode chest, and the fists cleverly transform out of the beast claws.
Sinnertwin has more articulation than the original. That's what I got to say about him! I mean, that extra articulation is nice, with the jaws and the balljointed beast mode necks (at the skull -- it's just hinges at the torso), so there is a lot more to do with him. But he's had less evolution to his design than Blot.
Hun-Gurrr holds together extremely well in torso mode. A friggin' lot of tabs. Tabs everywhere. That results in a very solid combiner robot. I can't find fault with their combined mode, Abominus. He may be the best of the new Combiner Wars-style guys. And he's made out of monsters, yo.