I have had it for 3 months now and I am quite satisfied. It is universal, so the connection was plug and play. It enhanced the volume, quality, and bass (always using the MAX function) of my car speakers. I strictly increase the volume on my speakers up to 40, as beyond that it starts to distort. Good range.
As for the negatives, I have the following to mention, but these are minor issues that you may encounter occasionally, so they don't ruin the overall experience.
The volume difference between 20-30 and 10-20, as well as 30-40, is minimal. I don't know why.
The Bluetooth works flawlessly, but it has disconnected me only once, and to reconnect, I had to delete the device and pair it again.
Also, every time the device turns on, the Bluetooth tries to connect to the last device it was connected to, instead of a list of paired devices.
I don't know about other users, but in my car, it doesn't turn on with the car's ignition, but rather with the press of the voice button.
At night, the keys 1-6, which are also function keys, don't illuminate enough to see their separate function.
I would prefer a pause function with the press of the voice button instead of mute, as I don't think anyone would simply want to mute the music they are listening to via Bluetooth.
I have only used the USB port for charging, but it managed to drain the battery level for a 2-hour trip (on a phone that wasn't managing the music and was idle with occasional app openings).
During phone calls, the person you are talking to can't hear you unless you shout.
TLDR: I recommend it as a first upgrade from your car's basic system to Bluetooth.