Ran the 10 beta for a bit until a driver issue caused all kinds of grief and I just went back to 8.1. Been running 10 release for a few weeks now and I have gotten used to it much more quickly than I got used to 8 originally. Still had a few driver issues but a quick trip to the manufacturer site for the latest drivers fixed those right up.
Couple of things to note though:
1) Updates are mandatory. That includes drivers released through Windows Update. This sucks because the driver in Windows Update have caused issues before and usually are not better than the drivers available at the chipset manufacturers website.
2) It automatically uses your PC to share updates to other people. Peer-to-Peer should mean updates download faster, but if you are on an internet connection with limits that is a bad thing. If you have multiple PC in your house you can say just to share with the other PC on your network which will save you bandwidth since just one can download the update and share it to the others. Or you can cut off that sharing completely. It's under advanced options in updates.
3) It shares your WiFi connection to your friends. Now, this is able to be cut off and only applies to folks who come to your house and it does not share your actual password, just gives them the ability to connect to your WiFi if they are at your house, but some people flat hate this. Cut it off if you worry about that kind of thing. Look up Disable WiFi Sense for instructions.
4) There are a lot of extra search options that share your search info with Microsoft. They can be cut off in the Search Option, but be aware that doing so means your searches will include only local content so you can't search your Start or Cortana for an application and if it isn't installed get a link to the site to get it from, or search your Start or Cortana for a recipe and get a web link to it. That is why the info is shared to MS, they need it to search the internet for what you want.
5) You can have just a Start Menu with no tiles. Just right click and Unpin from Start all of the tiles then resize the whole thing down to just the Start menu. Bad news is that you can't pin anything to Start then as Pin means tiles.