I've flown all three cabins with Virgin, and I don't think that PE is worth the extra money that it costs to upgrade from Economy, especially of you have family to pay for. I didn't think that PE gave a big increase in service standards, bearing in mind how much extra a standard PE ticket costs (Upper Class is a different story, but that's a lot of money to pay!).
Unless you get a special rate the cost of PE tickets is considerably more than Ecoomy, and I would rather spend that money on having an even better time for the 14 days I'm in Orlando, and grin and bear it for the 8 hours I'm on the plane. You could upgrade your hotel, buy annual passes for the parks instead of hoppers, hire a nicer car, stay for a few extra days, etc, etc. All of these things are worth more to me than a slightly more comfortable journey there and back.
Just my opinions of course, as everyone has their own perception of value.
Regards
Rob