Just thought I'd add my bit about Serengeti's, I put them through the ultimate test at Chatswood Grace brothers (remember those days before they were Myers!). Coming down on the escalators I thought it was getting rather hot so i took off my jumper, as I did this I managed to send my sunnies 5 stories down under the influence of gravity!
Expecting the worst I was suprised to find them still intact with not a scratch (that I could see anyhow), the frames were just slightly bent out of shape.
I'm on my second pair of serengetis and I know they're expensive but their worth every cent. I'm going to try and look after these ones a little better!