You could go either and it would be a Good choice.
PC: Half cap-half sidewall, Race bases(faster but need to be waxed regularly), Stiff for a park ski but not Armadas stiffest.
El rey: Full cap(less durable than the PC), Standard Armada Bases(good bases not Armadas fastest), Stiffer ski which = great pop, El rey is a price point skis but is one of the better price point skis on the market.
Both would make a great allmnt park ski.
I personally have the AR7 and love it. Sometimes I wish it was faster (specifically on spring days), but Im happy with the amount of Flex I got with it (I wanted a stiffer twin tip).
If your hitting only jumps and few rails, go with El rey. Its a killer allmnt park ski that's stiff.
Or if your Planning to hit everything in the park and want longer lasting ski, spend the Extra money on the PC. It's worth it. Plus at 5'6'' 140lbs It will be plenty stiff for you.
I say buy in the off season as they are both cheap now.
http://www.backcountry.com/armada-pipe-cleaner-alpine-ski
http://www.evo.com/skis/armada-el-rey.aspx 
