Agree 100% with this post. Samsung products are ****. They may well be the best selling Android phones on the market, but that is just marketing.
I personally use Sony Xperia Z, a superior phone in every conceivable way. Never had any problem with it. The PC Companion software works on my Win 8.1 machine like a charm and their updates to the OS are spot on. It's an older telephone now, Z1 and Z2 have been released but they don't give up on their support for older telephones.
I uninstalled the Samsung Kies software the other day and am now getting the MAStartupCleaner.exe message on reboot. I only installed it on my machine because at the time my girlfriend was using a Samsung phone. She now has a Sony Xperia Z2 and doesn't know how she put up with Samsung for so long.