As of late I have not been impressed with pioneer H/U's, the last couple that I and friends have had have been lack lust at best.
My new HU, is one that is dicontinued so it can be had at a good price, look at the JVC KW-NT300, the new one is the 350. It has a dual core processor and the nav maps are loaded on a SSD ( nav by naveto, does the OEM GM nav ) and it loads up super fast when the truck starts and then its ready to go. Reads a USB stick super fast and the picture quality is excellent. You can find it on Amazon for around 500.
Amazon.com: JVC KWNT30HD 6.1-Inch 2-DIN Navigation Touch HD Radio: Car Electronics
plus the built in bluetooth is nice, and it actually fit in the cavity, no smashing or fighting wires to get it in. I wish I would have upgraded to this ALOT sooner