I personally went for the faster, more memory and with Android version - this one is the old Windows CE and I am uncertain how much more you can do with it. The Android version at least I can install a different app if I don't like the music player, sat nav or want to put Torque or something on it.
I think both versions do the same thing out the box, just the Android version I thought would be easier to tinker with etc. It's near double this price though for a new one. Will let you know how I get on when it arrives next week.
If it's crap, I will just move my Alpine in from my old car.