Fulltone SupraTrem gets my vote, and space on my board. It's not transparent at all, adds some mids, cuts some highs but is complete bypass. It feels like a really old Fender Trem and very Sproingy if that's what you're after. It's quiet as can be. Sometimes I turn the effects all the way down just to get the glassiness it offers, and dial my amp a little different. It makes my Fender guitars and amps very happy.