Hi there. Try a quick search for a lot (really, lots) of info on this.
Click on the link on the right hand side of the lighter blue line labelled 'search this forum' and type in key words like 'HKT' 'Phuket' 'worth' 'business' etc. Search similarly for PE....
I found this for you
http://www.flyertalk.com/forum/showt...ht=pictures+PE
In sum though, the cost for biz return is THB 2000 (USD 57) more than economy. Lounge access (although HKT lounge is under upgrade works). No access for onwards flight in PE to JFK. Biz in A300 is old, b747 ok or very good (depending on which configuration 747 used). So, for 1:15 flight time, how important is lounge access x 2 and a better snack/meal, and maybe a better seat (or at least legroom)? Up to you.
Cheers, TK ...... and welcome to FT!