No doubt there were well built machines that have stood the test of time. It is hard not to look at these things from your own personal preferences as I am sure there may have been things you would have much rather have continue on. History has already shown no SLR's met with success without instant return mirror. Can you imagine SLRs today without instant return mirrors? However, we see even today's users adopt manual lenses on their auto everything cameras and are using these old lenses in stop down mode.