Custom ROM's are an unstable mess on most Android devices, Samsung being particularly notorious for poor developer support. Don't be surprised when 911 calls don't work [1] [2] [3] [4].
Moto phones are pretty legit software-wise. Almost stock Android. They do have some very useful features however for what they offer (gestures and such).
They are owned by Lenovo though. Since ownership their OS updates have been much more regular. YMMV.