The grandstream one is not as slick looking but I have yet to find any solution with a keypad that is narrower.
Not to mention the price difference! at around $900+ for the doorbird with integrated keypad and you still need an IP based device for it to communicate with like the grandstream handset with 7inch screen or Tablet unless you only want mobile only.
If they come out with a more narrow unit I will definitely pull the trigger.
Grandstream also does not require a dedicated screen. You can use mobile. Though I have rarely seen a commercial grade doorbell like the Doorbell units that do not have a dedicated screen. And yes the fact that Doorbird is ONVIF compatible is awesome!
If you still have a ST hub, until HE gets Ring integration, I would think you'd be able to link Ring to ST, link the ST and HE hubs together, and access the Ring devices indirectly through that? Actually a new HE owner, converting quickly after buying a ST hub. I knew that Ring was at least partially supported in ST, so the plan for me was to either stay with ST if I liked it, or buy HE and try to link them together for devices the HE didn't support but the ST did.