this right here.
the thall and the ar7 are very similar skis. same company (obvously), same construction (or very very silmilar), same dimensions, similar flex, etc.
if you plan on buying a ski that you will ski exclusively in the park, buy the t-hall. if you plan on buying a ski that you will ski in the park, but will also ski it all over the mountain, buy the ar7.
don't worry about stiffness and all that mumbo jumbo (i just said mumbo jumbo lawl) just follow this simple guide and decide (if this is your only ski) whether you plan on skiing all park (or like 90% park, 10% all mountain or more) or if you plan on skiing park and all mountain.
"karma is like a penis, if you dont use it it'll fall off" - soulskier
"skiing over bitches" - hauser
"disregard social life, acquire cheese" - oreopancake