Windows 8 is very stable since I remove my ENGTX 580, ( the Nvidia Kernel was crashing all the time, I'm now using an old ATI GPU with plain Windows drivers) the major problem I have is the hot corner that pop up when I want to press back in the browser or when I get close to the corner in a program menu, I disable them with Classic Menu , all true classic menu bring back the start menu, I disable that option as I prefer use the start page. Still I prefer Windows 7 as no Metro Apps interest me, they are toy style software with very limited capability. All true the mail apps is not that bad. Last week they release a 500+ mb update, kind of mini service pack
You will have to learn key short cut if you want to use Windows 8 with efficiency
I found Windows 8 enough stable to upgrade my Workstation to it, on my daily use PC, I have Pinguy ( Linux) and on my gaming PC I have Windows 7 , so if I will have only 1 choice, I will have to choose Windows 7, as it's the one who do everything. ( since I have problem with Nvidia GPU, I can't game on my Windows 8 PC )