My favourite of the current combiners are Menasor and Bruticus. Having Optimus as a combiner has also been a lot of fun since you can choose from a whole range of characters and he never looks wrong.

Biggest surprise was Jazz being a combiner in POTP. Dont know why they haven't done a repaint of him.

Wish they would of done proper sized feet for the combiners from the start instead of the hand/feet combo.