Ok, so i picked up an AppRadio 2 last week to replace my AppRadio 1. Then Saturday I picked up a Droid Razr Maxx to replace my iPhone 4s. Here are my first thoughts.
Hardware: I just used a cheap HDMI to micro HDMI cable from Best Buy and plugged it into the back of the Headunit (into the HDMI port). Thats all it took, no special cable required. I actually ended up picking up an HD Dock for the Razr and i am mounting that on the corner of my dash so it will be a quick and easy plug and play for both HDMI and Micro USB (to charge). Other than that it took about 5 minutes to get the cables hooked up, and you can leave both the iphone cable and the android cable plugged in and it works fine.
Also the 2 way switch that i had for the parking brake wire works perfectly on the AppRadio 2, no change needed
Software: The initial setup was kind of a pain and it takes some getting used to. The AppRadio and the Android pair via bluetooth, and that can take 30 seconds to a minute to fully connect once you have plugged in the hdmi. Pandora causes the phone to disconnect via bluetooth but then works fine. You have to tell your phone to mirror your image via HDMI for it to work when you plug it in. I set it to "remember that setting" so once i get it my car, i toss it in the dock and i can leave the phone alone. There are no pop ups on the phone for you to press or open like on the iphone. You press pandora it opens, you press Apps and it opens the AppRadio app (which stays running at all times on the phone). Then from there you can select your apps. Downside so far is that only CarMediaPlayer and Auepeo work for Android (along with the contacts, calendar, maps). Hopefully eventually more apps will work (Rdio im looking at you). The plus side is that if you back out of the appradio app (using the back button on the headunit), you can mirror the phone screen on the headunit. So you will see your full home screen. Now you cant control it from the headunit but you can still use other apps and display everything up there. I have my phone mounted where i can touch it without being too much distraction. This allows you to use google maps navigation up on the headunit screen and bringing the sound through the radio, which is nice because that means a free navigation system. Also keep in mind since it mirrors the home screen any texts or anything will show on the headunit (you can actually see the status bar including battery and signal and all that). So if you are talking to someone you dont want your passenger to see, stick to Pandora because all other apps show it.
Overall it works well and for the price of the unit, it isnt too bad. I'm hoping that there will be more android apps made to be made functional, or maybe a 3rd party app to allow it to read ALL inputs from the head unit, even from the home screen, which would make it amazing. I have a feeling it is possible.