Hi neverclever, thanks for getting back to me and sharing your thoughts on Loona. Glad I could help out.
Have you heard of the Looi robot by TangibleFuture? It combines the speed of processing in a smartphone with robotics to create a petbot interface that might offer the fastest processing speeds among petbots.
Looi was recently on Kickstarter. But watching videos of it again I realise it’s only a text based interface.
The only talking robots I have experience with are Loona and Moxie as my Vector is offline. Another robot that might be worth looking into is Ropet.
If you are looking for speed I would be cautious of buying a robot and would probably just go with a smartphone.
YouTuber Miraenda has practically every talking robot and I’ve added a video from her channel in case you wanted to compare the different robots response times.
There is also a virtual avatar from Batata you download as an app on your phone that might have the petbot qualities with the speed of smartphone processing.
Hope this helps.