I've been using this model for a number of months and it's quite good. Plays from SD card, USB, bluetooth. Has a bendable arm so is good for tight places. Sound quality.. decent. Not crisp but thats typical of anything FM based.
Generally it's a good unit, and worth the $8 I payed. Now banggood is doing a sale and you can get it for under a fiver
I bought a unit that looks exactly the same from AliExpress for around the same price. Always had a buzz on the sound and was low volume meaning that it couldn't put out many tunes. YMMV. For what it's worth I've used the same phone with other BT devices and my new head unit without issues.