maybe its just me but i think the chronics are very heavy in comparison to something like the armada ar7 i was looking at both and went with the armada because of how light it was but if your set on line then i would say the chronics.
A flex in the middle
Maple Macroblock Core
Not 100% Symmetric (121-92-117)
Weigh a little more depending on size
Good for all around skiing on the mountain when you want to and good for park.
Stiffer ski made for big jumps/pipe
Skate Deck construction (Next year they are going to construct them with sidewall in the middle and then skate deck at the tips and tails.)
7-ply (Maple Macroblock next year/some skate deck.)
100% Symmetric (115-85-115)
Comes in bigger sizes
Double Carbon Ollie Band
Good for Urban, Park, Jumps, Pipe
demoed both yesterday and i thought i would like the chronic more but the step up was soo much fun... next years have full sidewall underfoot and skatedeck at the tips and tails. they changed the sizes so they are no longer 177 as the max, i used a pair of 181's. really poppy.
also keep in mind that step ups have an extruded base, and will therefore be slower than the chronic, which has a sintered base. keep in mind that next years step up will have a sintered base, however.