Bought 2 of these, his'n'hers - she has the back cover with attached front cover, mine is in a hardshell case - both fit on this cradle without any problems. The rubberised base stops it slipping around - my only very minor niggle is that unless you have long fingers, it takes 2 hands to remove the phone from the dock. I have long fingers, the wife doesn't.
Update 5th Dec 2013: my wife has upgraded her S3 to a LG G2, which also fits nicely onto this cradle. Visitors with an S4 and HTC One have also used the cradles and they've worked fine. I guess that as long as your phone has the right connector placed centrally at the bottom, it will happily sit on this stand. Am so impressed I've ordered another 2 cradles for our spare rooms - no-one in the family uses Apple products any more so all visitors will be able to stand their phones in these docks overnight!