OMG, finally someone else! I did a short one-shot fanfiction about Nu52 Red Robin vs pre-reboot Red Robin a while back. It's more an introduction to the concept of the nu52 trying to overwrite the pre-reboot with "better" work. I focused more on pre-reboot Red Robin and telling it kinda from his POV.
I liked your shadow works here and the facial expressions are nicely different. Rather than just having them both be angry and fighting, they seem to look different.
No doubt in my mind, New 52 Superboy would win in a fight… though he'd probably not want to fight in the first place.
Nice going with this, the anatomy is quite nice on both of these guys, aside from maybe classic Conner's head, looks a little small for him. I do think classic Conner's six-pack is a little too pronounced given the outfit, but then I have seen the comics do that too