Moto G, Moto X or Samsung Galaxy Grand 2?

They have no music app like other android phones have which are not from google, it has no my files and no task manager. Without these apps can I survive? It has a google music play which requires a net connection to operate, can I download music from Mp3skull and store them in my phone without a 3rd party app for music or I can download any music from google play music absolutely free and store it in my phone? It gas no expandable memory but 2 years free 50GB of google drive, what type of things can I store in google drive and can I even store some apps in it? What should I do to clear my RAM when there is no task manager? How can I store my ppt presentations in it without my files? And last question is that Moto G has quad core processor and Moto X has dual core processor, so which processor is better and which phone should I get? As a conclusion I should buy Moto G or Moto X (will I survive with them?) or should I go for Samsung galaxy grand 2?

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