I'm pretty biased, but I'd say HELL yes. Unless you are running an iOS specific game that is exclusive to iOS, or for a rare app that you can't find in windows form.
Games: superior IMO, but that's because I load desktop games onto it. YMMV and this is only personal preference. Woo GTAV on my tablet!!!
ITunes remote: not sure how it works as a remote, but hey you can always just install iTunes onto the surface taking away a level of complexity.
Web browsing: No comparison, you see the web in it's full glory the way it was intended.
Music: this I'm not sure of, I'm sure others will chime in.
how are you able to run gta 5 on the system when gta 5 has not been released for pc? Are you emulating it from your 360 or xbox one? Just curious because thats awesome.