Though Marler isn't everyone's cup of tea, he is far from an idiot, there's many prem teams that would benefit form his presence IMO
I think I could like Marler as a Wasp. Smart, wind up merchant; just what you want to nettle the oppo. Knows exactly what he's doing, and a real character. Sussex boy and family man, though, so not sure he'd seriously contemplate a move.
Hate him as a Quin, and would hate him anywhere else. Not entirely dissimilar to Lol or Hask, perhaps, and in a different way Matthews (more Martin Johnson, and was delighted when he defected as he always caused us grief as a Quin, and sad when moved on).
There's a few flyhalves that have also seemed to up their game against us, and at times beat us single-handedly: Goode (Leicester), Gops and Walder (both Newcastle) and maybe even Fiver at Sale/Glos amongst them that were all good to bring onside -- Twelvetrees, too, though he's always seemed erratic so never coveted. I don't have Smith in this group (yet), and def wouldn't swap for Umaga or Atkinson.
Not sure quite how similar to Marler, but love the niggle that JTA has brought. Maybe only room for one joker in a team/squad...
Genge may be of similar ilk (measured niggler skillfully playing the ref and oppo), while Sinckler always strikes me as a bomb waiting to go off and hurt his own team, and Ward just seemed plain nasty. It's a fine line, and one that Hartley seemed to wobble at least when not captain.