I think the XTool A30M is an excellent Bi-Directional scanner for most home use especially for its price. I love that it gives a voltage readout as soon as you plug it in. I use the D9HD at work a lot and like it so much I bought the D9S for home use.
Most negative reviews are People not understanding the scanner and its functions. They buy a bi-directional scanner hoping to control there vehicles functions but find that it doesn't work on their specific vehicle. Most functions are model-dependent and limited by the vehicle's computer, or only work on certain makes and models. This limitation is not a fault of the scanner but rather a result of vehicle design and the individual buying a scanner thinking its going to perform magic.
All in all i think its a very good Bi-Directional scanner.
You might have already seen this video but here is a good review.
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