I have the Harmony 550. It eats batteries, probably because the backlight comes on now and then for no appararent reason. I wish I could select the order of the screens for each device, for example if it's not on, and I want to turn on the AV Receiver, I hit the Devices button, then the AV Receiver button, then have to hit the menu advance button 10 times to get to the power on button for the AV Receiver. It's easier just to turn everything off (with one button) and start over.
From an all devices off state, it's only two buttons - Activities followed by the specific activity button you desire like watch TV, watch a DVD, listen to the radio, etc..
I like it, but when I got mine about 2 years ago, I paid close to $150 or it. I've often felt as though I should have returned it for a refund, but never did.