My personal opinion is that if you are having to ask the question for yourself then it is not worth it. I haven't cruised disney but have been on two other cruises and one was with a verandah. I knew our
travel agent and he scored us a verandah room at no additional charge. To us, it was nice but I would never pay for it. I've flown first class as a wedding gift on my honeymoon before also. Nice but again, I would never pay for it.
My DH and I went around and around last year even trying to decide on deluxe vs moderate hotel at WDW. So many people think it is all about what you can afford and if you can afford it why wouldn't you do it? We can afford and still won't do it while our kids are still young. Chances are your kids are going to like it for a min or two then ask if they can go do something else on the ship anyway. Just a guess here. After much hemming and hawing last year on the WDW room it ended up being a $700 difference to go to a moderate. Total fun money.
This is my long winded way of saying that if I were you, I would not do it unless you think you are going to use the holy crap out of it. A thousand bucks can buy a lot of cool things for kids that age and you might want to think about if someone were to give you that money before you left what you would do with it if upgrading weren't an option.
I bet I get flamed for being so blunt but why not just put $500 in a bank account for each of your kids for their cars when they turn 16, etc. Or 1k in the bank for your next vacation?
Debbie