Leaving it on balanced should be fine for gaming. It'll use max frequency when you're actually running applications. Only time I've found speedstep to be bad is when you're doing a lot of on-demand processing off an idling CPU. In which case it usually takes the processor a few milliseconds or tasks before it reacts and "accelerate" to max frequency. In that case, it is very job/industry specific (ie. loading/processing images or data on demand).
High performance will not affect gaming as once a game loads even on balanced power mode, it is constantly running and the processor will be at constant high frequency. I'm running OpenXcom (game that can run on a single core computer) right now in Window mode and it is running 3.84GHZ on turbo (i7 4770 3.4ghz) with balanced power mode.
For a home user, there really isn't any point to using high performance mode (speedstep or c-state off). I just set balanced mode with sleep off. Unless you need the quick processing power coming off of idle. Only thing I can think of where high performance will benefit a home user is loading webpages with lots of graphics maybe, but even then, it would have to be high-res graphics. Only reason I know is I work at a medical imaging company where the CPU plays a huge role in processing x-ray images on sporadic demand. If you're running a server however, having high performance is crucial (that is if you're not worried about spending on power) as you want the quick response time for client requests.