I think that if you are only ever going to be working on domestic vehicles then that would be a good choice. I have the md802, its the same thing with global support and love it but it mostly gets used on European and Asian cars. I have also noticed that at times updating can bit a bit of a PITA but a call to customer support worked it out for me.
Can you answer any of these questions about the md802?
How comprehensive is the live data?
Can data lists be customized?
Is there graphing and is it fairly quick?
Is there live data for the abs system, specifically wheel speed sensor data, or just code reading for the abs system?
Are there any bi-directional capabilities?
Thanks