Unreal is a really advanced software, with which many people create astounding projects. What I do get from this discussion is that there are quite a few people having basic problems like long loading times. I myself have been waiting for an hour (starting up the first time: wait for it to load (shaders), then create a new project, and again: wait half an hour.
So, my constructive criticism is: expand your regression testing, and also use machines that have existing versions and use the regular upgrade process. If you only do regression testing on newly installed machines, you will miss out a lot of bugs. I know Unreal is a real sophisticated software program, but basic bugs like long loading times should have been detected before release. And yes, I totally accept that there will be things that need fixing, after it has been released to the public, and I can live with that.