My first time flying CP is going to be a DragonAir flight from San Francisco to Hong Kong to Phuket and then back the same way. How does economy on these flights compare to say economy on southwest, united, or american airlines? It is obviously a long flight so I'm curious if upgrading might be worth it.

If I was going to upgrade my wife and I, how many miles would it cost me to upgrade all 4 legs of our flights to business or first class? Or how much for each leg?