When was the last time you used Windows? 7 has been nothing but stable for me and isn't plagued with problems as it once was, ever such a long time ago. I don't see OP complaining about that, either. Reminds me of Volkswagen owners... they think that they're such premium cars, but that's only because they haven't driven anything else since the 90s. Things change
I have, however, had to reinstall Mavericks after a few months on the MBA due to some kind of keychain corruption that couldn't be fixed.
OP, the i5 should do well for what you intend to do -- it's still a fast computer. I would only be concerned about the usable life of any of the 2014s, although they do at least resell quite well, or retire into a media PC / server nicely.