I've flown many long-haul flights, probably close to 100 trips with at least one leg of 10 hours. I've probably flown business class on about 40 of them, either lie-flat beds or almost-full recline with the similar pod configuration. Once I flew first class (15 hour flight) but it was pretty similar to that airline's business class cabin which I've flown quite a bit.
As far as I can recall, I've never paid the full-price business class fare (on 10+ hour flights, have definitely done it a number of times on shorter flights), it was either: 1) paid by my employer, 2) I bid for an upgrade (some airlines let you do this), 3) I redeemed miles/credit card points for a business ticket, 4) I had an upgradeable economy ticket and used miles to upgrade class, 5) I got a free upgrade at the gate (only happened about 3 times, but this is the best).
There's definitely a big difference between stuck in the back like one sardine among many and having a lie-flat bed, both in terms of experience and how you'll feel after the trip. Is the $6-7k for round trip or one way? That's not a bad deal for that route round trip, but I would also consider the following:
1) What are the alternatives, in terms of cost and experience? If you can snag an exit row or premium economy seat, that alone could elevate the experience at much lower cost.
2) Do you have credit card points you could redeem for the business class ticket, or to upgrade from the economy fare?
3) What does the extra $5k or so mean to you? If you have a NW of 20 million, it's a lot less of a financial burden than if you just graduated college and have your first job while trying to pay back student loans. Since you're even asking I'm guessing you're somewhere between those situations so it's really up to you.
I've done some pretty rough routes on economy, 2-3 leg trips of over 24 hours total duration. You'll get through it, just download some shows to keep yourself entertained. But if you can afford to treat yourself for a special occasion trip, business class will put you in better spirits and probably make the whole experience more memorable.