Just test drove a 2012 392 Yellow Jacket 6 speed, a 2012 Redline 392 auto, and a Jazz Blue 2013 R/T Classic with 6 speed and STP. Here are my thoughts comparing them to both my current 2010 DY SRT and former 2010 R/T H/O Classic. I hav now driven every combination of V-8 Challenger produced since 2008, so I have definitely been around the block on these, so my review is not comprehensive, just some initial impressions...
2013 R/T Classic: Seemed louder than my 2010 SRT and braking is much improved compared to my 2010 R/T Classic. There is not as much travel in the pedal, and the brakes grab pretty hard though not as well as the Brembos on the SRT. Acceleration felt about the same but more linear than my SRT, and I could not really tell a huge difference between the two. Obviously, my car likes to rev more but again not a big difference. Handling wise, more body roll than my SRT and way lighter steering, which I did not care for. However, the upgraded ratio on the 2013s means less input is required to get the car to do what you want. Overall, I was immensely impressed with the improved dynamics over the 2010 R/T I had and would buy it over a 2010 SRT if I were looking between a new R/T vs a used 2010 SRT. Plus, the minor upgrades to the interiors of the new ones over the 2010s is a nice touch, except for the dotted pattern on the center console and around the NAV screen. It looked tacky.
2012 392s: I hate to say it, but I was actually really impressed with the auto 392. It felt so much quicker than my 6 speed 2010 and a tad quicker than the 6 speed Yellow Jacket. Obviously, not as fun to drive, and the whole paddle shifters are a gimmick that I would rarely use. BUT, the paddles were surprisingly quicker than I expected them to be. Compared to the 6.1L, way more linear and more dramatic power delivery. Way more torque. The 6 speed 392 shifter felt tighter, and the clutch let out lower than my 2010. The R/T was a easiest to drive actually. Braking felt the same. Handling was a bit tighter with about the same amount of body roll, but again less input required due to better steering ratio. New steering wheel rocks. The only interior thing I did not like as much were the seats. Though the materials are better, I felt like I was sitting on them rather than in them. Still great seats though. Overall, driving dynamics between the 2010 vs 2012 are like someone drinking a huge Starbucks coffee with a shot of expresso (392) vs. a decaf herbal tea (6.1L). They really woke these cars up over the last couple of years since I've driven them all!
Well, there are my initial impressions. If I had purchased a 2011 R/T Classic instead of a 2010 two years ago, I'd probably still have it. Now that I have a 2010 SRT, I would actually consider getting a 2013 R/T Classic to replace it IF the car were my sole transportation. If you are looking at used SRTs with the 6.1L vs a brand new R/T with STP, I'd actually recommend the new R/T over it believe it or not, since it newer with warranty and performs similarly. For me, I think the 392 is the natural progression. They are trying to get me to buy the YJ they have. It is equipped exactly how I want it too. Only option is the YJ Package, so no sunroof or NAV. It is growing on me after seeing it in person (used to hate the wheels and stripe), but I may just wait until 2013-2014 to see what other colors come out and or engine options. They also had a 2010 B5 SRT supercharged there, but I did not drive it though I should have!