GOgroove FlexSMART X2 Bluetooth FM Transmitter

I've owned the GOgroove FlexSMART X2 for a year now (the flexible longneck version). In short, it has performed much better than expected and the sound is impressive and satisfying, considering the nature of a Bluetooth & FM transmitter device. It pairs automatically within seconds (at power-up). If it broke, I would replace it immediately with an identical device; that's my litmus-test for being a satisfied customer with all my gadgets. I do understand the "non-goose-neck" version does not have a power button, which may be an issue for some. However, the current-draw is very low and could be left on for days & days without draining the car's battery. My primary desire from this device was good-sound-quality. Although I have used it successfully many times to accept incoming calls and it does work very well, MUSIC is what I wanted and it delivers as good as could reasonably be expected. There are two factors that most all of these type devices will currently suffer from : (1) Bluetooth's Low Complexity Sub-Band coding compression or SBC (2) FM transmission/receiving process. Given these two limitations, Bass response is solid and virtually unaffected. I have a "decent" system in my car with 10" sub, Infinity speakers, and multiple MTX amps. Bass will likely not disappoint most listeners in the majority of situations. However, high frequencies are where you will notice the quality degradation from the Bluetooth SBC compression the most. The "s" sounds in lyrics are noticeably slurred ("sibilance" for the audio inclined). "Noticeable" is quite a relative & subjective term. If you're the uber-audiophile type that actually believes they hear a difference with $1k speaker cables and headphone break-in periods, you need-not purchase this or any other Bluetooth device. The sibilance "s" slurs are subtle, but can definitely be distinguished from a hardwired connection. During 99% of music playback, this is transparent to the listening experience and the quality sounds GREAT! All Bluetooth communication employs a "Source" (or sending) device and a "Sink" (or destination) device. Most BT audio devices today use a "Profile" and a "CODEC". A Profile called the Advanced Audio Distribution Profile (A2DP) is designed for streaming audio in stereo. Another Profile called The Audio Video Remote Control Profile (AVRCP) enables a Sink or destination device such as the GOgroove FlexSMART X2 to control certain functions of the source/sending device (e.g. cell phone, iPod, etc.) such as Pause, Play, Next Track, Previous Track, etc. But it is the audio CODEC (compression & decompression) algorithms that make the difference in audio quality. All products using the A2DP Bluetooth profile are REQUIRED to implement Low Complexity SBC for audio, which does support up to 345 kbs for hi quality stereo audio. However, many devices do NOT currently support this maximum bit rate and manufactures do not often state what the actual SBC bit-rate for their particular device is in their specifications (including the GOgroove FlexSMART X2). It should be noted that there is nothing stopping BT manufacturers from implementing other optional audio CODECS (i.e. native MP3 or AAC) in these devices. If they chose to include these optional CODECS, sound quality would be much improved as no secondary compression/decompression step would be necessary. Currently however, the Bluetooth A2DP profile only REQUIRES manufactures to include the SBC audio CODEC (much the same way that Blu-Ray is REQUIRED to support PCM and DD audio, but may OPTIONALLY also support Dolby True-HD and DTS-HD Master Audio tracks; most Blu-Ray discs now include these OPTIONAL lossless audio tracks). Perhaps the future will see nearly all Bluetooth devices supporting native audio MP3 and ACC audio CODECs. Until such time, the GOgroove FlexSMART X2 is a wonderful $50 gadget that has opened-up my music library on my smartphone and made it available in my car. This is literally a life-altering experience if you spend much time in your older car which didn't come with baked-in Bluetooth audio system. Sound quality is really very good and will feed your car's stereo with gigabytes of music from your Bluethooth devices. I have tried some VERY poor quality overseas FM car transmitters and many are complete JUNK. However, this GOgroove FlexSMART X2 is a phenomenal device. It probably deserves 5 stars, but I gave it 4 due to the possibilities for improvement mentioned. If you don't currently have Bluetooth in your car, and you are even a moderate fan of music, you could not possibly spend $50 on anything in the Amazon kingdom that will bring you this much enjoyment. P.S. Since it also doubles as a 5V (1 Amp) USB charger, it just an unbelievable bargain. You can also connect non-BT audio devices (older portable MP3 players, iPods, etc) through the 3.5 mm jack via a wired-connection. GOgroove really did think of everything! Gotta change my rating to 5 stars! :-)