While I personally haven't used TypeScript, I can say this - worry not, about its roots. The whole code's open sourced on Codeplex, and Microsoft's commitments to open source are growing. Plus, it was personally overseen by Anders Heiljsberg - the guy's a freaking genius when it comes to language design. The only thing I have against TypeScript is the syntax - personally, I prefer CoffeeScript, due to its Ruby-esque syntax, but that's just me. So if TypeScript's being favored by peeps at your company, go for it!