I had no trouble doing so. In the first couple of days I was just a little confused about the settings, but after a while I understood the idea. The phone is able to hold the Lollipop system well, no problems.
I have the Verizon version (5.1) and lollipop works great. It does take a little getting used to if you have never used lollipop before but you should be able to make the transition very quickly.
I think some of the problems people had were with early versions of lollipop (5.0, 5.0.1). You might want to hold off if you have a carrier version that only offered one of these version but if you can get 5.1 or 5.1.1 then there should be no issues.