I think it depends on your goals. Some ideas: If you want to work for a startup then you'd probably need to learn open source tools (though startups use the MS

I think it depends on your goals. Some ideas: If you want to work for a startup then you'd probably need to learn open source tools (though startups use the MS stack, too). You might also find that a detour into OSS helps you bring fresh ideas back to your MS work. If you need a job and/or like working with MS stuff, then stick with that (and be shamed on HN ;). If you want to build a product, then it doesn't really matter--it's more important to bring something successfully to market.