It really depends upon the product, right? Let's assume we're talking about a web-based business app. If the MVP already requires some complex business logic,

It really depends upon the product, right? Let's assume we're talking about a web-based business app. If the MVP already requires some complex business logic, then I'd probably choose an old-school stack. I personally prefer Rails. But I'd probably pick .NET. Above all, my metro area is full of .NET people. It'd be much easier to find/hire collaborators in .NET. I'm comfortable and productive enough with .NET on the technical level. However! If I could get away with just putting up a couple Lambda functions, then that's absolutely the path I'd choose. It's an MVP. Let's get this boat rowing ASAP! In short, product and market influence the best technical approach.