I honestly don't know anything about the one you linked too. Personally, I have this one:
I actually bought it two years ago and had it in my Jeep and when I sold the Jeep I kept the radio I've been so happy with it. Now, granted, I don't have an iPhone but I was told that if you jack the iPhone into the USB jack you can directly control the iPhone from the stereo. Or so I'm told. I actually have a droid so the 'hands free' calls that I make are all controlled through the blue tooth. I THINK that if I turn on the voice activated dialing it'll work, but honestly, I NEVER initiate a call when I'm on the road. The unit can be set to 'auto answer' an incoming call, but I never set it. I always used the manual answer and to do that all you have to do is hit the volume button and it answers.
So is it better? Hard to say. Most stereos are based on personal opinions and experiences. I'm merely sharing mine. I know this weekend I'm replacing my stock AM/FM/CD changer with the Pioneer.