Bests & Worsts Reviews from Amazon

I bought this for my Macbook Pro, which has an HDMI port built in, to use at home. Resolution is extremely poor. It would give me the 3840x2160 size, but it looked awful and the next size down option was 1600x900, which was ALSO low resolution. Tried upgrading the cable, that did nothing. I use other 4k monitors in my office with zero problems or clarity, so I know it's not my video card. I feel sick about my purchase because you really can't return these things once you've opened them.