Hi, Using MBA 2011 1,7.. Yosemite made it slow-working, slow-reactive, it's sad for me . I wont downgrade back. Any way, Yosemite is helpful for me just because of the continuity, and while I don't have iOS 8, it's useless for me! What about the interface? it is very beautiful, nothing bad or negative to say about the new design, I liked it very much! Hope I'll ever upgrade my mac to RMBP! How can I downgrade back to Mavericks?