Appodeal usually publishes the average eCPM they are getting by country by format/size in each country. The last report was April (the June one will probably be released this week).
In general, Appodeal has very good eCPM across the board. When I have compared it to other networks Appodeal has always provided a higher eCPM.
But these are just averages with some tweaking of the waterfall, you can beat these numbers easily. This is US/iOS/banner for the month of April for two of my apps on Appodeal:
The average reported by Appodeal:
Mexico and Spain banner ads as reported by Appodeal for April:
Same data for cuadros 2 on Appodeal: