Car scanners are great to have for those weekend mechanics who are into performance tweaking. However, when you get a scanner, make sure it is not a cheap knockoff of a real one. You need to know what is inside the electronics you buy online. If you want a great OBD2 Bluetooth scanner, you need to know what type of circuit components it has. Otherwise, you will be left with a device that cannot do all the things you might want it to do.
Now if all you are interested is in a simple diagnostic report, then the knockoff models might work for you. However, what mechanic, even amateur mechanic, wants inferior tools? You do not have to pay a fortune for the real thing. You just need to know it when you see it. A real scanner is going to let you see and control the whole on-board diagnostic system. You just need a combination of the right scanner and the right software.
On-board diagnostics of cars has come a long way. You can control all kinds of things. You can control the engine performance and pretty much everything. If you have a fancy new sports car, why not tweak out that horsepower you can get. Maybe you want more looks and less oomph to get more gas mileage. Well, you can tweak that too. When you want, you can reset things to factory defaults. Just have the software and the right scanner. They all plug into the same OBD port, but not all scanners are equal in what they can do.
When you are buying a scanner, ask to see the breakdown of what it is capable of doing. Ask about limitations as compared to a fully functional OBD2 Bluetooth scanner. You might be surprised at what you are getting.