I've owned a Sony 70-400G since its launch day and it has seen 4 diffferent bodies strapped to it (A700, A580, A77, A99).
Lenses certainly outlast the cameras, having said that it is beginning to look a little rough around the edges now.
On my trip to Japan, I took 11,000 images and probably 70% were shot on that lens.
Some Sony stuff and now some Nikon stuff (shock horror). Sony cannot supply what I want so rightly or wrongly I'm branching out to someone who does.