A Launch 431 V+
I need to help someone with a intermittent but persistent problem and my other readers don't give me visibility into the entire system. Besides some cheap BT readers, I also have a CarChip, two Autels and an Innova. The Launch gives me the ability to exercise certain portions, make changes to settings, etc.
Unrelated to making this decision as I already bought the tool at the time, my son's crosstrek since threw a transmission code Subaru is refusing to deal with so we have to fix it ourselves. This tool shows me a lot more data.