Yup, that's my general Guerrerrol set. Gammadrain is actually pretty bloody good. And no, it doesn't outdo Nature Dance for pure damage, but Guerrerrol has better stats and is faster, so you will not only heal back damage but you'll also kill in 1-2 hits if you're hitting for super-effective damage.
Terruffalo is just outclassed. Hell, use Grandlan. Tons and tons of move variation there. Terruffalo is bulky, and that's about all I can say for it.
Skirial. Again, outclassed. Parafuse is neat I suppose, but I'd rather, y'know, kill stuff? Because this game already relies way, way too much on luck. I don't want to waste time with status unless your name is Irroadium. And even then, Skirial just straight dies to that thing. Not worth it. Would rather use a Titomaton or Dussocket or Mondevol there and just paralyze, then go for big damage.
My ideal team is something like Grandlan/Pandourbit/Leonatar, Sacroloon/Oristar/Martiagle, Mortrex/Deciced, Mondevol/Erroir/Dussocket, Fiendour/Titomaton, Banyardan/Guerrerrol/Remullion/Dramagon.
There are others, but for me, those are your basic top tier pieces to a great team. Obviously don't go heavy on the electric/magic/earth types, but yeah.
Manamon like Fauntozaur, Tylovile (if played physically), Bombusect, Submenno, Dragomier, Fowliture, Bellaard, Tenshaino, Garganchan, Ekspunge, Tarboo, Hydrake and Frorgerol are great second-tier options.
And pretty much everything else that isn't mythical is either underwhelming, straight-up busted or just...not inspiring. I want to like sullorb, for instance, but its moves are awful. I want to like Turoison, too, but same deal. Ditto Steelion. Ditto Placebot. Ditto Arctana, Domestress and Rhinodyo.
Check out my Manamon text walkthrough at the following link:
https://www.dropbox.com/s/z8ls3rc3f4mkb … n.txt?dl=1