There's lots of opinions regarding premium fuel vs. less expensive alternatives. Here's mine.

If the lower quality fuel results in detonation/pinging, the knock sensors will retard the ignition timing to prevent engine damage. Under normal driving conditions I doubt most people would notice the decrease in power.

I'd be more concerned about carbon build-up. You can avoid this problem by periodically using one of several fuel additives, but you'll probably still end up putting the same amount of money into the tank either way.