Mechanically, it looks great. The traditional DIMM sockets always seemed fragile too me, and they are very tall too. Two screws that go into a real metal backplate seems like a much better idea.
It's also much simpler electrical signal path, so the memory can run faster and draw less power.
Historically, the trade-off between soldering everything into a motherboard and socketing everything was only the cost of the sockets. With current technology, the socket limits the performance of socketed components and increases power consumption. A CAMM2 socket has a much lower performance and efficiency impact than a DIMM socket, although it still has some.
The best trade-off between upgradability and performance is likely to be support for standardized CPU and GPU modules that have in-package RAM and use only differential serial busses, like PCIe, to communicate through the socket.
