I've had this combo (not purchased as combo) for about 2 yrs now and the only complaint I have is the "sticky" keys on the keyboard. Sometimes when you get going at a good clip the friction between keys cause a slight hesitation in depressing the keys. That is all. Otherwise, I have no problems. Connectivity has never been an issue, even from across the room. Battery life is good. Functionality is good. It works for me.
I have both of these both thay work very well The track ball is second to none, I will not use anything else. The keyboard works as expected with no problems. I would like them to backlight the keys but overall it works very well. and will buy again.
I purchased the K350 keyboard about year ago. From the beginning, the keyboard has been giving me trouble. It DOES NOT transmit signal through objects. My desktop is less than 6 ft from the keyboard location, and the keyboard skips, pauses, etc. 99.9% of the time. The only thing between my keyboard and cpu is the monitor. There is nothing more annoying than, half the characters I type not showing up. So, for these reasons I"m very dissatisfied with this piece of junk. DO NOT BUY THIS, you will break it in frustration, LOL.