One big difference with Mini Connected is that it does not come with a sim card so all "connected" functions use your iPhone data connection. In fact, what Mini calls "Mini Connected" is almost the same thing than what BMW calls "BMW Apps" (and not BMW Connected as you might have thought).
Mini Connected enables you to display your Facebook & Twitter feeds, use Google Send to Car and listen to webradios. The interface and functions are almost identical to what I described in my previous post about BMW Connected.
The same annoying bluetooth audio streaming deactivation happens when you plug your iPhone in the snapin but you can fix it in the same way that I previously described:
Another difference in the Mini is that you can either connect your iPhone in the snapin cradle or using a Y cable. Both options should provide the same functionality. In my case though, I haven't managed to play music using the "plugin" option in the Mini Connected menu when using the snapin. It does, however, work when my iPhone is connected using the Y cable. I don't know if this is due to a problem with my snapin or its model (there are unfortunately many different snapin models with support for different functions and nobody seems to know which snapin does what).
I also encountered the same limitation for bluetooth phone contacts syncing than with BMW: I have more than 3000 contacts and it seems that this exceeds the capacity of the car as I can't sync my entire contact database to the car. This sucks and shouldn't be the case nowadays.
One information you might be looking for and that I can confirm: the iPhone 4 snapin works with the iPhone 4S.
Besides the bugs described above, I must say I love Mini Connected and that it makes for a perfect in-car entertainment system. There are some other thoughtful features such as the ability to let the car control the music it plays depending on your driving pattern. All in all, it is well worth ordering it with your car!