Wow, you guys can be entertaining...
Unfortunately we'll never really know exactly what happened with the 4S because Apple is not really about disclosing their issues. Surely there was a percentage of the phones with hardware issues. On the other hand I remember some people going to 4-5 exchanges and still having issues - which pointed out to problematic configuration because of old data maybe, or some apps which were behaving weirdly under 5.0. Then the devs patched their apps most likely, while Apple solved some of their manufacturing/quality issues, and updated iOS. There most likely must also have been carrier issues i.e. what this person discussed a couple of pages ago - most likely some carriers had some low level provisioning issues with some customers etc. Finally, the phone is set up agressively in terms of configuration, which didn't help.
So most likely you guys are both right and both wrong. But in the end who cares? I think in the end the advice would be to never buy smartphones when they come out... it's good practice to wait some months before buying. The same applies to non-Apple products.