I do not care about fast or slow date change. The power reserve is a good point, but I don't care about that, either, with the rotation I have that's not relevant. But it's a good movement and should serve you well. Not sure about replaceability, either, tbh. I know I read it somewhere, but can't remember. As you see, I'm quite easy to satisfy. In the tech section there is a thread explaining all aspects of the vr and vs movements, replaceability should be treated there as well.
I've never used supermirrors myself but read good things, I don't think that having or not a website is that relevant, much info isn't updated or even accurate, best you use the forum for spec info.