@Quoth: A Clara should trounce an old Kindle on that front (ghosting), though (i.e., same hardware generation as the PW4/KT4, what the OP mentions is something like a KT or a KT2 (too lazy to pinpoint exactly, Amazon's marketing naming scheme is horrible, use
the wiki for meaningful names)).
Anything earlier would be a dicier comparison against a similar Kindle (in terms of release date), but Kobo really picked up the pace w/ the Mk. 7 gen.