SIMD is coming to the browser but not with JavaScript. The Dart VM is fairly close to adding native support for SIMD operations. This should add another speed boost for game developers targeting the web.
It depends on what your goals are. There are definitely cases where defining your own type is the better choice serialization comes to mind. I err on the side of portability though. Since operator new and malloc both take size t, and size t represents the maximum size of any ...
