Agree with Hemi Rebel, depends upon what you want to do with it and how much you want to spend. I have a Matco 1400 which is identical to the Actron CP9580, does a good basic job of reading and clearing codes, freeze frame, some graph capabilities. Generic stuff, but very happy with it. The most flexible (and way expensive!) would be the tools that are bi-directional, can work at the OE level, such as the OTC tools encore. I recently saw a demo of this, unbelievable! As an example, for a diesel ford truck, can even activate the exhaust filter cleaning process, read the number of hours on the battery, etc., etc. Tempting to get one of these (in particular, the Matco Maxme tablet which has a bluetooth OBD II connector which is way cool), but likely won't use the additional features very much.