I'm not sure which model is, but a friend of mine has a Samsung Android (just got it earlier this year), and it's incredibly slow and clunky feeling. Apps are always crashing, the operating system seems slow and laggy, the camera takes forever to take a photo, among other things.
The iPhone 4S is hands down the best phone I've ever used, in my opinion. Again, not hating.
it really all depends on how much dough you drop for the phone. i've had two android devices, the LG Ally and the Samsung Droid Charge (which is what i currently have). the Ally was about $79 brand new and was clunky as hell. i remember at one point, the photo gallery took over 15 seconds to fully load and would eventually crash after flicking through a few times. now i purchased my Droid Charge refurbished for about $50, but the new retail value of it was $199 at the time, i believe. i've never had a problem with it, other than the fact that the battery is total shit which can easily be fixed with a car charger.
moral of the story/tl;dr - you get what you pay for with both, really. unless your friend just has shit luck with phones