What exactly are you doing on the HTPC? Controlling XBMC or Plex? Browsing the internet?
I use a Logitech Harmony remote to control my XBMC and haven't had any issues with it. If I ever need to do anything outside XBMC, I use a K400 and have zero issues with it. The first one I bought had terrible signal strength and issues receiving my inputs. I returned it to Best Buy and got a new one and I haven't had any issues since with it. You need to make sure you have clear line of sight to your Logitech dongle or the keyboard is very spotty. It has a hard time being read through my entertainment system (I built it myself out of solid oak).