The ingredients are exactly the same, but close:
PPA Adipo
1R, 2S Nor HCL 25 mg 25 mg
Yohimbine 3.75 mg 3 mg
Caffeine 90 mg 100 mg
Aspirin 40 mg 0 mg
The little bit of aspirin in the ppa is going to doing hardly anything in terms of fat burning. The only advantage to ppa is an extra 0.75 mg of yohimbine. However, it is not worth paying nearly twice as much for half the amount.
I have used adipo in the past and had excellent results. I feel that it is the best fat burner on the market, both from a results standpt and a cost standpt; better than any ECA stack that I have tried, including xenadrine.
It's your call, but for my money, I have to go with adipo.