Some electric grinders can get a little warm while grinding a larger amount of beans. To be safe, go with a conical burr grinder. You'll get better consistency of the grind and there is very little heat generated from the friction of the grind.

Do you want to know the secret to a great cup of coffee? Buy premium-grade beans or better. That's pretty much it. Most of the other "tricks of the trade" are just that - tricks. Marketing gimmicks, mostly, because commercial coffee houses and retailers need to hit their margins and can't afford top quality. That's why they're always "blending" so much. It's a cost-saving mechanism...and most drinkers don't know the difference anyway.