Electroneum is completely unrelated from the other two projects, no? Why compare two XMR forks with the mobile mining currency.
They are all Monero forks. Te mining ETN have is not real mining but just a simulation of mining. Difference is that ETN collected $40 millions in ICO. They took huge premine and part kept and other part gave to those that gave them $40 millions. I do remember during ICO they lied about that some important Monero developer will help them develop ETN. No matter the money they struggling all the time althho all they need to do is copy paste Monero code and Monero infrastructure. Oh yes, they basically run v5 code I think without one important anonymity aspect.
Masari is just copy paste. I guess that they will stay forever.
AEON started soon after Monero. And since Monero had so many changes was quite different a year ago. Now it is getting closer and after next protocol upgrade will be close to same.
AEON have biggest community. ETN spent lots of money spend into marketing. AEON have huge development found that was all gathered through donations.