Asus has announced Lollipop update for ZenFone 4, 5 and 6. Which will be on air in April 2015.I think you should go with Moto G 2nd Gen coz you will get the taste of latest android update in that while in Zenfone you will have to see whether it will be upgradable to newer android version or not
ZenFone 5 is powered by Intel atom dual core processor with hyper threading enabled, which gives it 2 virtual core and Android recognize it as Quadcore. It has 2GB of RAM.
Moto G has 1GB of RAM.