Countless threads are dealing with this question: should I pay the extra for premium economy or for business class. There is no straight forward answer. As an analogy, the same problem exists for hotels: should I go in a two stars or a four stars? So to make your decision, you should consider a number of factors:
- the seat (in business class, cradle? lie-flat? fully-flat? - in premium eco, extra seat width and pitch). Check the airlines' website and http://www.seatguru.com.
- the experience: check reviews on websites such as http://www.businesstraveller.com/discussion or http://www.airlinequality.com/ (keeping in mind Skytrax is selective in the reviews they are publishing).
- pre- and post-flights amenities: lounge access, fast-lanes, transportation, ...
Then only, you'll be able to decide whether the extra services are worth the extra money. Keep in mind this is only for a few hours, but of course a good business class service is great experience.