I own a Moto G, never had any problems on it. Tho I'm not often playing games on it, just Clash of Clans, Real Racing 3, and defenders. I usually use it for social media and stuffs.
For the camera, i never had a problems with it to tho its lacking in megapixels. But when you just upload pictures to social sites, an 8 megapixel camera or 13 or 5 you can't spot the difference.
If you can get it extremely cheap vs a nexus 5 like pretty huge difference, get the Moto G. But if the price difference is just less than $50, go with the Nexus 5.
Or just ignore anything I said and get a Graphics Card. :DD