The problem is, they weren't lying at the time the ads were made. There's evidence to suggest that Apple's data centres are simply unable to cope with the demand and they're having to throttle it, which does have an effect on the quality of the results returned.
What are Apple supposed to do? Magic a couple of massive server farms out of thin air overnight? Those things take a hell of a long time to plan, design, build and fit-out, and Apple are, in fact, already doing precisely that. There's no instant fix, however.
Regarding Siri's beta status: it's plastered over Siri's webpage on Apple's own website in a very visible orange label. If that's what some of you consider "small print", I suggest you go visit an optician. Apple aren't hiding this.
No, they're not going out of their way to make it clear it's a beta in their TV ads, but then, Google never bothered with that nicety either, and some of their features were in a beta phase for years. And they've tripped up a few times as well: remember the brouhaha over Google Buzz?
Not everyone has a clear speaking voice, so Siri was never of interest to me, and I've had no better luck with Android's equivalent, or even with my occasional tests of Nuance's Dragon Dictate engine (which is, I think, the same engine powering Siri). Anyone who expects a machine to be better than a human at understanding spoken language needs their head examined. My own family have trouble understanding me at times, so how the hell is a phone supposed to be any better?
As for the naïve notion you have that there's no lying in adverts, two words: "unlimited broadband". Now that is a flat-out lie.
(There is, however, one thing the iPhone 4S does offer that the previous model didn't, and which isn't subject to a "Beta" label: Apple are finally offering a 64GB iPhone model. That is of far more value to me than any form of speech recognition.)