@mtaalam,competition is very tight with mpesa having the upper hand in terms of agents,and registered users. Mpesa also has ATM withdrawal. If zap can add ATM withdraw,it will boost their numbers. It also costs more to send money cross networks. A mpesa user pays the sending + withdrawal fees which is higher than that of a registered user is withdrawing. If you receive money from zap and you are on mpesa,you pay 30/ more than the normal withdrawal charges. You can reverse an mpesa transaction withing minutes,last time i checked with Zap,it was 48hrs. It all depends on what you are looking for. Its good to have both services active and use whichever is convenient for you at a particular moment
'A stone is heavy,and the sand weighty; but a fool's wrath is heavier than them both.' (Proverbs 27:3).