Your first priority in buying an amp should be how it sounds with your room and ancillary equipment. The power rating and all other specs should be secondary or even irrelevant - no need to obsess over impedance matching, max power levels, etc., just focus on how it sounds to you.
Unless, you need to drive inefficient speakers to ear splitting levels in a large room, then the power rating becomes a major factor. You wouldn't rule out a car because of too much extra power for 65 mph, so why short yourself of a good amp that happens to have more power than you'll probably use.