Thanks to all the replies, I finally took the plunge. After upgrading using the Media Creation Tool, it installed leaving me a whopping 100mb left on the C: drive. :evil: I took a deep breath, and purged the restore and upgrade folders, making this a one-way trip. I now have a healthy 10Gb free, even after reinstalling all my apps. After a few days' break in period, it seems fairly snappy and reliable.
Has anyone heard anything about how Recovery will work now? When I was on 8.1, I could create a recovery, but you're only allowed to do it once due to licensing or some such. Will we be allowed to make a Win10 recovery? yes, I know I can download the ISO and make a USB off that, but the Recovery has all the drivers pre-installed, and that save many many many headaches (not having touch drivers installed on a tablet is downright painful).