Sorry to butt in, however I do have some (legal) experience with this type of issues, and it's a lot more complicated than that.
Firmware issues are not covered by the warranty, unless they make the player completely unusable, i.e., in this case, if the player couldn't play a DVD Video at all, or a SACD or CD for example. None of the issues with the 999ES's firmware would, in court, qualify as being a warranty issue, even when, being an "ES" unit, something better should be expected.
And no, firmware or software bugs don't qualify, in court, as defects in workmanship. If they did, most software companies (Microsoft as the prime example) would be bankrupt by now.
Defect in workmanship has to be something physically visible - a shot capacitor; a faulty lens assembly, etc.
On the other hand, most consumer laws do allow buyers to return their purchases when the performance is below their reasonable expectations. So the weight of the problem lays flatly on the reseller's shoulders - if you are unhappy, you usually have one week *after you find the fault* to return it for a refund, and the reseller should refund you directly and then bug Sony (or their distributor) for a refund if they wish to. The deadlines may vary from place to place, but you get the idea.
In the cases I know about, disappointed customers always got their money back from the reseller, not the manufacturer, and in general the reseller did the background work and had their money back to.
However, one thing to bear in mind: this only works if you file your complaint with the reseller (and, optionally, the manufacturer) as quickly as possible, in writing. Also, never wait expecting Sony or any other manufacturer to do firmware fixes. Get your money back and, if they fix it, buy it again (probably cheaper). That's actually the best way to exert pressure.
Of course, if Sony Marketing decides that this is ruining their image, they may decide to start fixing the issue and everything will be good. But Sony NEVER, EVER did that in the past. Odds are they'll simply replace the 999ES with another model... Actually, one is already in the works...
After all, how many customers are they loosing with this? 10? 20? Is it worth the investment to fix this? Nope...
Sad, but that's how capitalism works.