I have the DM02. The quality seems pretty good and I really like the way they have made the motor easy to configure.
The torque sensing works well but the settings need a lot of tweaking so you need to be comfortable with that.
The engine pulls OK but is a bit noisy. If I were to do it again I would use the dm01, which I hear should be more quiet and is more powerful. The q factor is annoying to me but should be similar to other retrofit mid drives.
I use the Shimano linkglide chain and casettes 10 speed. Highly recommended!
The chainring on the dm02 is not narrow wide and the chain will fall off in the two lowest gears. The tsdz2 narrow wide chainrings fit and I have ordered one of those from AliExpress.
Feel free to ask any questions.