Google is SO unpredictable when it comes to updates. I own a Nexus 4 and LG Pad 8.3 GPE and my Nexus 4 within 2 weeks of the initial release of Lollipop got its update. My LG Pad 8.3 received Lollipop a month after that. Three weeks ago I received 5.1 for my LG Pad and last week my Nexus 4 got the 5.1 update. Just the reverse.
It seems official Google and GPE products get updates first.