I don't think I would have much preference, as long as the area is green and I could own a lot of land! (land with high speed internet service, of course!)
Are you talking about content purchased from the Minecraft store? Any purchase will stay linked with your GamerTag/login, so when you log into the Windows 10 version or vice versa it will be there.
I think I found the site pretty quickly after searching for skins and packs a couple of years ago. This is basically the premiere site for minecraft related stuff.
