Sorry to bump this old thread but I have the exact same problem.

Harmony 880 had extremely good range. I could bounce the signal off the wall behind my head and all my devices would work properly.

With my Harmony One the range isn't nearly as good. I have to very carefully aim the remote to make everything work. I had Logitech send me a replacement unit and the second one was no better.

And the battery doesn't last nearly as long as the 880 battery. It constantly drains no matter how much or how little I use it. The drain is so bad that it doesn't really make much difference how much I use the remote. Every four or five days it needs to be recharged even if it hasn't been touched.

All of this is ridiculous. Especially compared to how good the range and battery life of the 880 were. All in all, the One is a big step backwards from the 880 since the touch screen really doesn't add any real benefit. They should have left good enough alone.