Sorry to hear TopSpin.
I've had the old o3 racquets break/crack on me, at the throat/bridge. None of the new exo's have cracked on me yet.
That being said, I've had wilsons, heads and babs crack on me, so I don't think this has anything to do with a particular companies manufacturing techniques or inspection processes, they're racquets, they'll break eventually.
What it has shown me is that not all companies are equal in terms of warranty procedures and replacements.
"how many times??!?"