Mac or Windows?

My new employer wants me to choose between a 13" MacBook Pro and a Lenovo machine running Windows. (That's all the specs I have.)

I've never used a Mac, beyond my brief, awkward experiences in tech stores where I try to interact with a Mac, get frustrated with how unusual things are, and walk away. (And this is after using Linux on the desktop for 10 years and leaving for Windows' greener pastures.) But the incredible popularity of MacOS X  -- and the neverending stream of defections from Windows -- is strong evidence that the Mac is worth learning.

Should I take the plunge, or should I stick with Windows?

This would be for web development, with actual development being on remote Linux servers. The machine would interface with the servers using sshfs or Samba.