Works very well, and correctly steps up/down to a stable 12v for my application.
Nice gorgeous display, readable with both input and output information.

However, it doesn't appear the display can be turned OFF, including its vibrant backlight. For a battery-powered application, that's an unwelcomed inefficiency, so this is more of a bench-only or unlimited supply use case. An on/off display button would be a nice improvement for embedded applications.

The CC and CV each have their own adjustment, which is nicely fine and multi-turn. The on-board display isn't lab equipment or anything, but accurate enough to dial it in.

Also, the included stick-on heatsink fits perfectly, but seems to max out a bit south of 3 Amps. If I leave it with a 3Amp load at 12v it gets unreasonably hot in steady-state and probably needs supplemental airflow.

I used it to provide 2.7 volts to a bicycle LED headlight mounted on a 24 volt scooter. I noticed I could see pulsing of the switching power supply in the headlight when when driving into rain. This isn't a problem for me, but you might want to add some extra filtering to the output if your application is noise sensitive..

love the clear box, easy to assemble, calibrated it with a good voltmeter and steady hand on the little 15 turn adjustment screws to make a 4 amp 4.2 volt lithium ion fast charger for my headlamp batteries (dual 18650s). With the output voltage screw set to 4.20 volts (with an external voltmeter connected to the output), i shorted the output terminals together to adjust current limit screw to 4 amps(on the converters digital display). I'm powering it with a 19 volt laptop power source (readily available at most Goodwill stores for about $3:00) and have been using it for about 3 months every day with no problems. I'll probably get another one just to have one in case i have to make a charger for something else.

This is a great product and very easy to use. There are several YouTube videos on this product that are very helpful. You can't beat the price.

Good, inexpensive, and works well when you calibrate it.
I will purchase another for another project.