I ran a small test on popcash as well and came to the conclusion that it was not worth my time nor do I think it was it logging even 10% of the impressions it should have.
I ran a test on a landing page of mine that normally gets 1500 - 2000 uniques a day. Here's the stats from the test.
Landing page stats:
Popcash.net stats:
Along with the posts I've seen about people getting banned once they request a payment and my small traffic test, I can't recommend them at this time.