Any process, whether it is sleeping or running, in Windows takes up resources and CPU cycles. You can argue to the percentages of what that is, if you like.
Which is where the wording 'never seen any benefit' comes from. The theoretical benefit is just too marginal to see with a human eye, then again in practical situations disabling it may result in visibly slower app startup times.
There was a time when I disabled everything possible from win7. I found no performance benefit in doing so, most commonly just the opposite when apps that relied on some rarely used service, failed to function properly. Turn of WPF - fine, untill you happen to launch software that's built on wpf.
The only tuning I do on win7 currently is turn off netbios helper, simple services discovery protocol, and every service in networking except basic ipv4. TCP settings I tweak by setting manual dns (google, opendns). I also disable remote differential compression protocol on gaming machines. Honestly speaking I haven't seen any visible performance gains in doing even any of the above tweaks (except the DNS setting which has been problematic with my isp).