Great sound quality for music, podcasts, and calls over aux or bluetooth. The mic doesn't seem to be very good though, as people can't seem to hear me well.

It works exactly as advertised. My only complaint is the sound volume is fairly low. It's still plenty audible if I adjust the volume on my stereo higher but if I switch to the radio after using this, I blast out my eardrums.
When I ordered mine, there was only the option "without a neck". It's acceptable but if I needed another, I'd buy one with a flexible neck because my cigarette adapter is in a slide out compartment fairly low on the dashboard. It's mostly a non-issue though because once you have it setup, you don't rarely need to touch it or look at it.
Overall this is a great option for people with older cars/stereos.

I got this FM transmitter so I could play music from my smartphone in my classic '68 Mustang. Bluetooth didn't exist back in the dark ages, so the AM/FM radio with a cassette player can't play anything from the 21st century. This device filled the need. The only criticism I have is that it's kind of clumsy to get it into the Mustang's cigarette lighter socket because the device "head" is bulky and gets in the way of pushing it fully into the lighter socket. After some fiddling around and rotating the head, I got it in and set up. In the Chicago area it's a little tricky finding an empty FM frequency on the radio without interference from nearby channels, but that's not the fault of this FM transmitter. I did get it working fairly quickly and was able to enjoy my smartphone music and internet radio. Anything you can play on the phone you can send to the car radio. Finally, it also gives you hands-free phone capability, which worked very nicely. It's not going to get any sound quality awards, but neither is the radio in the car it plays through!

The sound quality is ok. It has a little static. Still worth the buy if you enjoy your online music more than the radio. It's pretty inexpensive so you get what you pay for.

Ordered the Vont VNT-FMT01 Bluetooth FM Transmitter, received it the next day. This is a nice device for less than $20. I'm actually using it a bit differently than most would. I have a Uniden SDS200 police scanner radio and wanted to be able to listen to the scanner anywhere in my house. I bought the Vont specifically because it has an Aux Input 3.5mm in addition to the Bluetooth connectivity. I plugged the speaker output of the scanner into the Vont 3.5mm receptacle, dialed up an unused FM frequency on my stereo receiver in the living room and viola, I now can now listen to the scanner from the comfort of the sofa. Or anywhere in the house with a portable FM radio. The only fiddling I had to do was to hook up a spare 12V wallwart power supply to a generic cigarette lighter receptacle and plug the Vont into the receptacle. I'm getting a good range on the FM transmitter; with the Vont sitting on the bedside table I get a good signal out to about 50ft in the yard. The frequency stability appears to be very good. I dialed in 88.9MHz on mine and it hasn't drifted a bit. Being a device sold worldwide, you can select the transmitter frequency in steps of 0.1MHz. In N. America we use odd numbers after the decimal point, e.g. 88.7, 94.9, 105.3, etc. Europe uses even numbers after the decimal point, e.g. 88.8, 94.8, 105.4, etc. Be sure to pick a frequency that agrees with your stereo receiver; the receivers sold in N. America will only tune the odd numbers.

I also checked the Vont for its intended use - Bluetooth connection to a stereo radio for music. It paired with my iPhone no problem. The music quality is good, maybe one notch down from a CD. There is a slight hiss when the radio volume is turned way up, which seems to be typical of all these devices. Once the music starts it's not noticeable. And I can confirm the FM signal it broadcasts is in stereo; a review I read for competitor's device said his was only broadcasting in mono, a real deal breaker if you enjoy music. The only anomaly I came across is I could not get the Vont to pair with my Alexa Echo. Not sure why; Alexa has no problem pairing with a BT soundbar or an older BT car device (BTCarKit) that I've had for years. Probably not an issue for anyone using this for its intended purpose of connecting your phone to your car stereo as you likely are not riding around with an Alexa Echo sitting in the passenger seat :)

As others have stated, there are no instructions shipped with the Vont. Simply go online and google "Vont VNT-FMT01 product manual" and you'll find a clear set of instructions. It speaks both in English or Chinese. Mine came in English right out of the box, but you can switch languages by pressing and holding the M button for 5 seconds if you want to practice your second language skills.

Overall I'm pleased. I'm going to get another one for my boat, and actually use it for its intended purpose: putting music from my phone on to the stereo. Oh, the one thing I haven't bothered checking is how well it handles phone calls. But lots of other reviewers have covered this topic.