Did you get the recent ELLA firmware upgrade - that seems to have fixed whatever was screwing up the app switching, although mine still seems to take a second or two to go to "full power" performance from power save mode.
Oh, and if any of your iPhone owning friends/colleagues etc are giving you grief over having a "mere" S3, so 'em the new Gallery app. The speed which it can do the spiral and "star wars titles" presentation of images is a good slagging-stopper.
(Not that there's anything wrong with an iPhone before anyone accuses me of being an S3 fan boy).