im 5 5 and i was so close to buying the 171 armada but i bought the scratches instead price wise.
youll def like the length for landing and grabbing plus its more stable. unless ur wicked light I would definately buy the 171. Im pretty sure most ppl here will agree.
im 5'8" and got 171's. at first i regretted it but now that I'm used to them I would never go back to 166's. NEVER! go 171. i ride 100% park and the added length is awesome for jumps and you dont notice it while spinning