Get the Moto X. If the $100 off applies to all storage variants, then try to get the 32GB for $349 (or 64GB for $399, if you can swing it). The Moto G is nice in that it supports expandable storage, but many things ONLY use internal storage, and that roughly 5GB available storage will fill up very quickly.
Given your tolerance of lower end phones, the Moto X might last you years. Go with the 32GB model, 64GB if you can afford it, and you'll be set for a long time.
Originally Posted by BigCiX
I'd wait for the new version.
Anyone considering a Moto E or G doesn't care about having the latest and greatest.