Most of the 419?? Blue items from final quests in zone areas and dungeons are so noticably better than the 397 gear I had that it's an easy decision to make. I have gotten a few 450 pieces so far, and do not have much Cata left and I am only mid way through level 88 with 3 1/2 zones to go. COmpared to BiS cata heroic items I think someone said once you were beyond level 88 they will be replaced by better.
As someone that gambled on older enchants and mats being worth a fortune at launch, I have to say I gambled and lost. I am seeing top end Cata enchants only going for 35-40 gold. The enchants for Mists are even ridiculosly under priced. If you have a stock pile of materials for enchants it may be worth making a few scrolls for gear to carry around in the event you get a good drop mid dungeon, but the increases in stats is not really a lot anymore from Cata. +40 vs +160. And I have disenchanted so much green gear my bank was overflowing in spirit dust and shards.