Hi,
The activation was always fine, no problems with that. You must register to a specific computer and you are allowed to change this registration every couple of months. Or just donate more and have more computer registrations.
Remember not to install to the Program Files folder, because it has some strict permissions set.
Currently the newest Windows 10 build unfortunately changed some system files, and the developer has to update AeroGlass acordingly, but I believe, that will work again soon.
The look and feel is far better than default Windows 10 and you can make it look like Windows 7 or anything else, you just have to pick the right theme atlas resources, which you can find on this forum (and it is not always easy to find it and install it). See this thread, i think the most compatible themes are the most recently added