Painfully slow!
It gets much better when you skip the auto scan and just go in to the module needed. Eg tonight I needed to get real-time data on the gear shift position.
It took about a minute to scan the VIN and give me the list of modules. 30 seconds to get into the transmission module and 30 more seconds to check off the real-time options and display.
A full scan of all modules I like to start it then go get a drink and come back.