Are you sure it doesn't delete? I use SyncToy at work and I rename and reorganize stuff all of the time and I never noticed any old files laying around...
No, I am still using Vista x86 and the problem with SynToy is if I make a change in a folder it will not do that change on the external HDD and most of it has to do with deleting files or changing files (this is important) like word and excel