No one can really tell you whether upgrading from economy class to business class is "worth it." It depends entirely on your financial situation. Spending an extra $4,000 to upgrade for a 14-hour flight matters a whole lot less if you make $300,000 a year than if you make $30,000.
It matters even less if your company is paying for it, as Business Insider did when I flew Emirates back from Dubai to New York in February so I could ride business class in an Airbus A380, the largest and most expensive commercial airliner in history.
Read more: I flew 14 hours in business class on the soon-to-be extinct Emirates A380, the world's largest airliner — and it was more luxurious than I could have imagined
While the chauffeur service, elaborate preflight lounge, three-course gourmet dinner, and inflight cocktail bar on Emirates were all unforgettable, most airlines do not offer services that extravagant for business class.
What you are paying thousands of dollars for — whether its Emirates or United — is the ability to sleep more comfortably. For some airlines, like Qatar Airways and Emirates, that means a pod-like seat that turns into a lie-flat bed. For others, it could just mean more legroom.
Only you can know whether that's worth the extra money.