It is a shame Reporo is not part of that list :/
On to the original question - I take your point it can be daunting, and trusting ad networks comes at a 'price' - and the price is not knowing how your traffic is being monetised
I think about it like this though - traffic monetization as a product (credit, vouchers, carrier billing et all) VS. traffic monetization through ad networks.
To make money as a product, you will always fall short somewhere - credit deficient GEOs like India, Thailand, South Africa / carrier billed deficient GEOs like USA, Canada, UK / physical structure deficiencies of vouchers and many more
If you were intent on only making money from 1 GEO - go for a different money-making model -- but at some point you'll start to get TH traffic, or IN - and at that point using an Ad network is crucial - as you have a whole company hunting clients who buy traffic where you cannot physically make money yourself because of your billing method (no matter which one you choose) - so, someone doing the work for you
TL;DR -- if you want to play in 1 or 2 GEOs, use whatever billing method is easiest -- more than that, to make proper money you'll need an Ad network
if you are interested to chat more, just register at Reporo as a publisher and make contact with me direct through the support mails - I am the Commercial Director
PS> all my own opinion of course ;)
PPS> I have built a lot of carrier billed products in the past, so can give you more info on these if you desire