Update: (two improvements and one problem on going)
-The microphone sensitivity has been improved as their were many complaints of low sensitivity when the Echo Show 10 (3rd Gen) first came out. It is now on par with the other echo devices.
-The motion (Person) detection is now activated and works well. One shouldn't use this as a "motion" sensor, as it is not instantaneous, rather it can take a few seconds before it can trigger a routine. So for controlling lights, it would be better to use a real PIR (Passive InfraRed) sensor rather than AI (Artificial Intelligence) person detection which takes longer to process. That given, the person detection is excellent for triggering less time sensitive routines such as a greeting or playing the news and reading your emails and calendar of events when it detects a person.
-The security monitor feature is still buggy after 5-1/2 months. While viewing in monitor mode, you get about 1 minute of video stream before it starts to hang and freeze.
Original Review April 11, 2021:
It's ok. The processing power has much improved over the previous Echo Show 2nd gen.
The tracking is okay.
Using the Echo Show 10 as a security monitor is buggy as after about 1 minute of streaming, the video feed becomes VERY laggy and halting. Eventually it stalls and the video feed crashes or freezes. So you get about 30 seconds to 1 minute of video streaming as a security camera before you have to back out of it and reconnect. I'm sure Amazon is working on improving this, and will report back in a few months if there are any improvements.
Can't use the motion detection that's built-in as a trigger for routines "yet" as a message comes up and says it is not supported yet.