Now I had the car a month or so, I thought it might be interesting for others (?) that I report my initial feelings for Android Auto vs Apply car play for the MIB II units.
AA was a lot more finicky to set up than Apple car play (ACP), which just worked straight away. It took a number of attempts of connecting, disconnecting, deleting and re-connecting etc. to finally get a stable connection. Now it connects first time every time, so I guess that's now a sort of a distant memory. By contrast as said, ACP just worked on the first connection with no errors at all.
My Galaxy S5 that I'm using was running Android OS 5 (Lollipop) originally when I first tried, but a week or so ago, I had the official notification of the OS6 (Marshmallow) update, and am happy to report that it's all good and still works a treat. IOS9 is installed on the Iphone 6 and as siad, works very reliably.
Now I have to admit that I don't tend to use AA for Navigation instead preferring the built in Nav Pro, but when connected I do like the way when you get a call, the head unit screen shows a large photo of the person calling (not just a thumbnail), of course providing you have a contact picture stored for them, and the whole thing looks really cool. By contrast, on ACP, although it shows contact thumbnails when browsing the phonebook, when a call arrives it's all big large pieces of text, which whilst is very readable (I guess the whole point of these systems is using the phone integration more safely), does to me look too simple and a bit "noddy". The ACP fonts are huge but lack any real sort of design, and on the 8" Nav Pro screen the whole thing just looks too boring and simple.
I do tend to use AA for music quite a bit though through Deezer and this is where (for me at least), AA, and ACP separate. For my tastes the AA implementation of Deezer and (Spotify for that matter), looks more polished than ACP. As said above Apple have gone for a minimalist look to the interface and in a high tech 2016 car just for me looks a bit too simple. AA is by no means busy, but to my eyes just looks a little nicer and most importantly functionally, works as well as ACP.
I've not really tried other Apps, the Maps or Siri vs Google text to speech's, effectiveness, but I did receive a text whilst listening to music on AA, and Google's TTS read the text out without any sort of "machine" accent, and when asked if I wanted to reply, easily picked up every word of my message and replied perfectly. To be fair, I'm sure Siri could do similar.
Having access to both an Android (Galaxy S5) and Apple (Iphone 6) devices, means I can get the best of both worlds, but for what I using either system for (which is mainly music) for me AA wins over ACP, purely for looks and so that's the one I tend to use. Who know however what IOS 10 will bring ?