I ended up getting the Alpine CDA-9857 after my Clarion unit was stolen. It has all the functionality and options that I wanted. I've been very happy with it so far and recommend anyone to purchase it or it's sister unit the Alpine CDA-9856 which is a bit cheaper.

Features
It has every feature, minus a DVD player, that one could want.

My personal checklist was as follows:
Company reputation: CHECK
3 Preamp outputs: CHECK
Sub Preamp: CHECK
MP3 Playback: CHECK
Satellite Radio Ready: CHECK(Sirius AND XM, with additional unit)
HD Radio: CHECK(with additional unit)
AUX Input: CHECK
Detachable face: CHECK

The ability to choose either Sirius OR XM was a big plus for me. The additional unit to make the satellite radio option available is $99 for either company. I know I'll go with Sirius but having the option is great.

If you have any plans on expanding your sound system then the 3 Preamp Outputs is a must. It will really simplify your life down the road. So, even if you don't choose to buy the CDA-9857 look for a headunit with 3 Preamps.

Style/Function
I like the look of it in my car however I still haven't figured out where the off button is. Silly I know but I end up just removing the face. I really wish the mute button was lit up like the other buttons because even though I've had it for a few months now I still forget where it is the few times I wanted it.

All of the controls are very easy to use and the menu options are easy to set. The screen is nice and clear day and night. It makes a quick glance to see what station your on very user friendly. One draw back is that if you don't put the face in the included case the face ends up a little scuffed up very quickly.

Performance
I haven't attached an IPOD to it yet because I don't own one, but I've heard mixed reviews on the display functions on it anyways so I'm in no hurry.

I had a problem with the regular radio reception at first but I fixed it by unplugging and replugging the antenna. I think I my have not pressed it in firmly enough the first time. You have to make sure it does a small click. If you still have reception problems you may want to check the factory grounding in your car. Since then however it has been nice and smooth. Everything is grand.

Overall Review
I would and have recommended the CDA-9857 to everyone around me. Those of you that don't want to shell out this much cash I say check out the CDA-9857's little sister the CDA-9856. Your going to be pleased with the CDA-9856 as well I'm sure.