I had done some reverting and upgrading on win 10 which fubared stuff and found a backup of 8.1 on a usb stick, so i guess it was just the 8.1 that came with the sp3. It installed a bunch of January updates and then showed "system up to date". As i say, there seems to be an "issue" with the sp3 in that despite it being a single system (much like apple ipads etc) just one change here or there, or an app installed that someone else hasn't, and all kinds of bugs are encountered that others don't. MS really need to stabilize the experience. So many instances of one thing completely failing for one user, but being fine for others (the recent youtube IE/Chrome stuttering thread being an example; a user experiencing a pretty annoying issue that others just can't replicate despite being on the identical hardware)
As i also said though, the poll rather indicates that it is not a platform wide issue, and that i'm not the only one who hasn't experienced this issue. Really a shame. It's one device, this is one of the key things that makes apple so successful, in that the lack of a million 3rd party hardware vendors means they can keep everything working well (on the whole) whereas MS now also have one device that they can try and focus on, and yet one machine to another offers a totally different experience. They really need to sort out their QC issues for the SP4 with regard to both hardware and software.