I have been researching this myself. I find I need one of these tools for work. My small code reader just isn't giving enough info anymore. I have chosen the Topdon AD600S to buy. The Launch brand will charge for update after a time & their expensive. The Topdon offers lifetime updates for this model. Only 2 years of free updates if you go with the Artidiag 800 model & above. Price to but is about the same. I found the Topdon on obdii365.com $199, shipped. The other brands I looked at didn't seem to have the capabilities I was looking for. So without breaking the bank & spending over $500.00 I'm choosing the Topdon.