I saw one sitting by itself a couple weeks ago at a dealer and I thought, eh, not too bad. I hated the back.
Then I went to a dealer to get a fuel filter and some other crap for my 06 and there was a 2009 and 2010 sitting next to eachother in the dealership. I got to stare at both side by side for a bit, sit in both, etc.
I may be biased, but holy crap is the 2009 a beter looking car from every angle except the side shot.
The new interior has it's nice points, but I still like the 05-09 better in some ways. As far as quality, yeah, some of the materials are nicer, others are the same plastic crap.
If I did not own a 2006, I would buy a new stang over the competition. But I am not so sure I am trading mine in for a new one anytime soon.