So I received the CPLAY2air Adaptor many here say they use and I have concluded that the Carllinkit 2.0 off Amazon are in fact the same devices down to the included instructions in the box. They may be slightly different packages as there are two versions of the Carlinkit and only one version of the CPALY2Air but they have the same configuration, the same IP address to access through the browser, the same interface, same connect times (between 20-30 seconds). They both have options to stream CD or DVD-quality audio (in the web interface) and they are both using the same version of the firmware when updated. I think they are just in different form factors. They do have different WIFI names, but I think they will all have different network names due to the need for randomness. I have used them both and find no differences between the function or the reliability of them.
I can recommend either one, but I would choose the Carlinkit model as it is easier to obtain (Amazon) and can be returned easily if you feel you don't like it, and it has a detachable USB-C cable that you can extend it if you want. Oh, and the connect light is on the top not the end of the device.
Let me know if you want or need any more information about them.