I can share my personal experience. When I decided to purchase AUX Link car adapter, I compared all the prices and it's really much cheaper to purchase it at the official online store
AUX Car Kits. The delivery took just four days. At first I decided to try to install it myself, but experienced some problems taking out the head unit. I didn't have necessary tools, so finally I had it installed in the nearest service center. It took just 15 minutes. So far I'm totally satisfied with the purchase.
Advantages:
- supports iOS devices, USB flash, SD cards, but there is also a mini audio jack for other mobile gadgets (MP3 players, Android and Windows smartphones, tablets, laptops, netbooks, PSP and so on).
- high quality sound
- can be used as a charger
- with optional Bluetooth module can be used as a car hands-free kit
- music control with buttons on the steering wheel and buttons on the car head unit (very convenient)
- read all music formats
- delivery is free and fast
- occupies very little space and doesn't spoil the interior
- now I can enjoy all my favourite songs without carrying piles of CDs.
Disadvantages:
- a bit expensive as I also ordered additional Bluetooth dongle to use the adapter as a Bluetooth handsfree car kit
- couldn't easily take out the head unit so I had to go to autotuning workshop
But all in all, I believe it's a good product. So from my point of view it's worth purchasing.