hi olby
thanx but i know for sp-404 and sp-606, don't worry.
until now i never operate in song mode.
this sp-505 is a real beast.
pitch scale function (in "music" mode)is killer; clip board too; the way to acces to banks pretty fast'n'easy; delete samples too; editing samples super useful: you can really take control over the chop and if not you can do it manually, but if chop is not accepted for some reason by sp-505 you can do it the same, that's dope! really near akai mpc mode.
i don't know sp-555 and sp-808 (this one i wish to try, but i've too many samplers!

), but i think that simply 505sp505sp505sp is the best sp in his category.
peace!!