I was happy with the performance on 8.1, but that only ran a few days before I upgraded. So yes, I agree that Windows 10 is probably the main issue, but it's very disappointing they couldn't do a better job on what should be a reference device. I do like Windows 10 in general but the glitches are driving me nuts.
It's great on my desktop. Just kind of ironic the Surface 3 is so problematic.