Yep, they're OK, especially if you want to try Skenzo or Google & can't apply direct.
I find lots of variation between the direct Ggl feed & the Ggl results via Sedo or ND, so it's worth trying a few out to see which performs better.
The DS feed also pays about $0.50 more RPM than the standard account at DS on pop-ups.
The downside is the net45 payout & the lack of any billing data (ie no credit notes/invoices or statements of account)
Verdict: worth a try!