I've been using an HP wireless keyboard/mouse combo for a year...the combo came with my new computer and I finally had enough of wonky functionality (the receiver was literally inches away from the keyboard/mouse yet it would still cut out at times). I received the MK550 as a Christmas gift through my Amazon wish list and the combo is better than I thought it would be. First of all the receiver is SMALL; I connected it to one of my front USB ports on my desktop and you can hardly see it (it also comes with an extender in case you need it). The keyboard and mouse haven't lost their connection once so far, the keyboard is high quality and feels nice to the touch, and the mouse is equally comfortable with a quiet click.What makes me laugh is that the keyboard has a "Media Center" button that links to a Windows Media Center application (reminds me of Hulu with free TV shows, etc.). I NEVER knew that came installed on my computer and now I'm having fun watching some of the sitcoms I missed this year. 

Question: Was the mouse you had perfectly good?
Answer: mouse yet it would still cut out at times