A:AnswerThere are 2 differences I have been able to see. I have also been searching these 2 TVs. They seem to be identical with very minor differences.
The feet placement and style are different, and the LF 621 has 20 watts speaker vs 10 watts speaker for the A810.
Supposedly the LF621 is the newer model...
A:AnswerCurrently the Firestick does not have HBO Max as an App you can download. However, the is a workaround you can find if you Google it. You can download the HBO Max yourself and install it. I did that about 3 months ago and watch HBO Max regularly.