Recently, because of depression of world economy, so many businesstravellers are asked to seat in down-graded class by their company. Therefore, the demand of even more slightly relaxed seat, Premium Economy is sharply increased.
However, in my opinion, this above mentioned class is the one for airline companies to raise profit with less stronger effort.
For the case of BA’s PY, it’s impossible to use lounge and in-flight meal is completely the same as Y class.
From my experience, it would be better for the airlines which have PY that they should provide lounge access and baggage priority at least.