Motorola historically has the best signal pull as they practically invented radio communications (I'm not saying they DID but they're HIGHLY respected). The Moto E also has a Nexus-like Android build (so it gets quick updates).
I know nothing about Huawei, though I hear ads for them during baseball games.
One thing to consider, that 4 GB of space will leave VERY little for apps. That space is the TOTAL in the phone, including the space the OS resides in.