Moto has never been a very good phone maker. Look back at the original razor flip phone. HTC USED to be good, back when the G1 was first released. Now its all about quantity, not quality.
That aside, samsung has treated me very well over the last 2 or 3 years. First with the s2, then s3, then s4. Hell i still have all of them and still use them for various things. (Time lapse cameras, Media Center remote, dash cam etc...) Very durable and reliable series of phones.