It is, I've got Windows 10 on my MBP and 7 on my iMac. After tweaking 10 you can make it nice and open.Windows systems are becoming more locked down too though.
I think my worry about OSX is that it'll become a full blown version of iOS with apps that you can only buy from the MAS. I don't think that will happen any time in the foreseeable future, mind you. But then I further worry that if I get too ingrained into the OSX/iCloud culture that it'll be difficult to move out of it.