I wrote the posted review. "Worth" is always a tough thing to judge for somebody else because you never know someone's financial position or comfort level. I look at it this way, if you add up every perk the math will probably not quite add up to where a private VIP is "worth" it on an empirical level, especially considering the other alternatives like the group VIP or express pass. (Unless maybe if you split it with another family). However, only you know the value you place on the hours or nights you save as well as what you believe the special experience is worth.
Its a great day and your kids will have a blast. You wont wait in line more than 5-10 mins for any ride and you can ride anything multiple times if you want. You learn some cool things and see some behind the scenes magic. The customer service will be excellent. But, it will be all for nothing if the cost makes you too uncomfortable to enjoy the vacation day.