As a lifelong SimCity fan (well, for the life of the franchise, anyway), I was thrilled about the possibilities of SC5. I'd take smaller cities for the challenge of managing a region. It's different, but that'd be a new challenge, one that I could embrace. But the always-online, server-only-save, component just rubs me the wrong way.
I'm glad I have a Mac and didn't rush to purchase this right away. By the time the OSX version is available, perhaps I'll have a clearer picture on the long-term viability of the game. At least I still have my locally-saved, full-sandbox Minecraft game.