I have a 550 remote, and after a lot of struggling, I ended up leaving the TV on all the time. There is an option somewhere to do this.
My problems ranged from power off sometimes working, then sometimes not working, then sometimes the TV would come up on power-up as though a hard reset had occured.
I had the latest firmware and software for the Harmony remote, and even did a hard reset, deleted all components, and re-adding everything. I also played for hours with the different delay settings. Nothing worked.
I have also found that with Harmony remotes (I had a 720 before), sometimes everything will work for months, and then certain devices will have power problems. Nothing works, and then after reloading the config 15 times, it just magically starts working again. Unfortunately there is very little out there in the way of affordable remotes.