I had recently the following experience: My H 655 wasn'it able the power ON a new device I bought. Logitech gave a lot of codes to test -> not major improvement. Well I could start at some 1 feet distance and without the repeater. Interesting thinks:
Logitech told me to try by turning the remote ctrl 90 degree (having the button facing left or right): this improved really the efficience. What curiouse idea they have to oriente this way the IR beam !
Secondly, I asked them if i'll have an improvement of the situation, if i buy a Harmony One. The answered : NO.

So my compromise is to handle with 2 remotes: the Logitech for most devices AND the original one for the specific one (here the original is much much better).