I've found that scaling the campaign is one of the trickiest aspects to get right.
The only ones I've really tested with any long term campaigns are MOBIPIUM, Evadav and Monetizer and out of these I'm currently focusing on Evadav (and just started a new follow along here) because this is the one that's brought me the best ROI in the past.Which one was the best in terms of general ROI including long term revenue
I make about $25/day with Monetizer as a byproduct of promoting Monetizer offers with the push collection option switched on. I would like to promote the Gotzha offers more because when I tested them they were OK, but the $1000 minimum payout from Gotzha put pressure on my cash flow so I'm keeping that one on the shelf for the future. Otherwise I've only done very quick tests of Propush and Push.House and I'm planning to explore them more this year.