Looking to add Carplay integration into my '09 and wondered if these units have come to a point of maturity that all kinks have been worked out and are performing flawlessly. I have standard non-HK audio.

 

Honestly not sure if they've improved however I can say, they've come down in price a lot! I bought mine about 6 months ago and it was best deal out there at the time...$499. Mine is similar to what you have pictured (I have the 10" version), and you'll see many brands...more than likely, all the same for the most part internally.
They do not work perfectly...very salty and at times, get's a mind of its own, What I dislike the most is that, when using this device, you are tethered to the power of your cell service. I like to use XMRadio a lot and when I am using this screen, when I lose cell service in a given area, I lose most of it's functionality. I'll flip back to the original Mercedes NTG system and continue listening via my in-car satellite antenna. Some may never experience this if you're in a metro/city area as cell service is widely available. I'm a field rep in Upstate NY and when I hit "farmland", I can lose cell service often.
Biggest headache was the install. The adapter block that goes behind/below the stock HU makes its a very tight fit and will require some tinkering. I have a 2013 with HK and it was a bear rerouting all the wiring and adapters. Then, you'll have the navigate through the screen setup where the in-box instructions become worthless. It was a lot of trial and error for me along with many YouTube tutorials. All in all, took me about a week to figure most of the bugs out.
It looks very nice and I receive compliments on it but it is not perfect, by no means. Many today are getting these modules that utilize all the same stock hardware but allows you to have CarPlay on the stock screen. Seems pretty cool and if I had the choice today, I'd probably go that route. I've always preferred a clean, stock look but this doesn't look too bad and when working smoothly, it's a very cool device.
Good luck!

 

Mine has basic audio and no backup camera so I'm guessing the standard audio screen is a no-go. Many years ago, my wife wanted a backup camera so I did a double-DIN unit. Now, I like the convenience of having Carplay. This car stays within the city so cell service is not an issue.

 

I dont have one but if i were to get one I would probably buy it from Amazon so if it doenst work right I can return it easily within 30 days. The reviews dont look that bad for them on Amazon, seems they work better in a C300, negative reviews for other models from my very brief search.

 

Also, if you really want (Apple) CarPlay, make sure the unit isn't only for Android Auto. They are not the same. Do you have an iPhone or an Android phone?

 

iPhone.