PM is new payment process as ECU money but in both payment process ECU is getting famous and popular because of advertisement on forum and using payment processor and safe exchange with Swapgold.com......
Anyway i have account in PM but after i exchanged $5 PM to LR i get only $4.63 it is quite low compare to ECU....
As far as I know, we can exchange 5 PM for 6 PP with other members. Similarly, 5 PM for 5 LR with other members. I don't know about online exchangers. I think you used online exchanger to exchange it to LR. That's why you got very less LR.
I haven't seen Ecu anywhere except in few forums like WTH and MGF. But I can see PM is used by many merchants like HYIP websites, online products seller websites, and many more. So I think PM is getting more popular than ECU.