Microsoft does the right thing here to give licenses away to startups. However, I would try to stick to their mainstream products which are likely to survive a

Microsoft does the right thing here to give licenses away to startups. However, I would try to stick to their mainstream products which are likely to survive a few years ahead and avoid the "to-new-unproven" ones, mainly to make sure the product is still developed and maintained 3+ years down the line. I'd go for open source any day, but that brings other challenges instead. :)