I have gotten to use the viewer (4.7.3 x64) for a bit now. There is too much new stuff to step through item by item. So, this my limited experience take. Regardless of whether I like the viewer, its having Viewer Managed Marketplace (VMM) compatibility makes it a must have for many Firestorm users.
Download and Install – Nothing unusual. All smooth and no problems. I did do an uninstall before adding the new version.
Performance – It is too early to say, but in general my Frames Per Second (FPS) are about the same as with the Linden 3.8.3 version, provided I use similar settings. I am finding it seems a bit faster in areas where I am alone. It has problems in areas built with heavy mesh use, but so does the Linden viewer.
After 30 minutes or so I start to get mini freezes and black screens. I get that with the Linden viewer too… this may be me and not the viewers. I notice that once the memory use at launch (300+/-k) climbs into the 2 GB range I start having problems.
Some users are having problems with no-copy avatar skins. They don’t render. A default Ruth skin renders. It is not very many. So, it is likely a hardware related problem.
The chat panel no longer has a minimize button. It is either open or closed.