yesterday afternoon, i did it too. of course, mine took forever and when it was done it magically deleted all of my apps! (oh yes, you can bet your bottom dollar that this sister was not too happy.) luckily, i thought ahead and i backed up my phone and made a list of all of my apps before i did the download. it took a little while, but now i have all of my apps back and everything is back to normal.
apparently there are supposed to be over 200 new features to the new operating system. so far, it seems okay to me. we'll see . . .