The new Explorer Club card is very similar to the old PP card, with one main trade-off between the two: the EC has no flex PQMs, but earns 1.5 miles per regular dollar of spending, while you earn 1 flex PQM for every $5 in spending on the PC but only get 1 mile per regular dollar of spending. Other than that, I think the two are identical. The catch is that you can no longer bank PQMs for a rainy year when you don't fly enough to get gold/platinum, as they have some long but annoying expiration date.
One interesting thing almost nobody seems to know: you can get back the $350 or whatever it is annual fee using miles, but only in the same year it's charged and only after it's been put on your statement. For me, that mean nailing the miles transfer for the fee credit in a two week period in December 2012 that I missed... hopefully I'll remember it this year. I think the ask was 20k miles for the fee credit.