I like doing a combination of Seafoam + full tank of premium after an oil change. Its done a pretty good job of getting the engine in my Focus to run well. When I first got it, it kinda felt like something was wrong with it. We did an oil change and it helped but after a thousand miles, it ran like crap again and even felt like it'd cut out at low speeds. The second oil change was done with Royal Purple 5w-20 high performance and it did a great job of cleaning the engine. I had started doing seafoam + premium because I red that it could just be a dirty injector problem rather than something serious. After the most recent oil change (its almost due for another one in about 500 miles), the oil was filthy, almost pitch black. The engine's running in fantastic shape, just with it had more bottom end power. It just feels really sluggish sometimes when you try to accelerate from low rpms.
That said, for my normal fillups, I use regular during late fall and winter and E85 the rest of the year. Last year, I had half a tank of E85 and the engine didn't want to start. It was about 40F outside. I don't really know if E85 was the reason or if it was something else but after switching to regular unleaded, the problem went away. Still, can't wait for E85 to be in surplus again. Paying $1.32 per gallon is pretty sweet and you can really feel the difference on the freeway.
People sometimes seem to get confused btwn "premium" and "top tier". Presumably, if you're saying premium to mean a higher octane rating, then it's a question of performance/mpg benefits. But it has nothing to do with keeping an engine cleaner. For that, you're looking for "top tier" fuels which have more detergents in them to prevent deposits.
You can use a regular 87 octane fuel but still have it top tier, just as you can use a 91/93 octane fuel but not be top tier. Top Tier depends on the gasoline supplier for the station you fill up at. Not the button you press.