I just installed a Harbor Breeze dual ceiling fan (small twin fans mounted either side of light) with remote control. Light works and both fans work on all three speeds, but whichever speed is selected, one fan spins considerably slower than the other, and the slower fan seems to have "drag" and doesn't spin as freely even when spun by hand with power off. Suggestions?

I would suspect that you have a bad unit. Since you say you just installed the, you should take it back, with your receipt, and get as replacement unit.

Yes, the slower fan probably has bad bearings or the like. Usually with twins, one is weaker or smaller. Exchange the fan.