Focusing all your might on a single platform can give you reliability and even better performance, and is less work.<p>Focusing on portability gives you a set of abstractions to build upon, that will take your time, reduce performance often, and limit your capabilities. But... it can also make you have a better mental problem of the problem you're solving, and allow you to move faster when underlying details change.<p>Like everything, it has ups and downs, I think.