I Pick these runes to boost her armor and dmg early game witch is very good for riven knowing what harras shes able to do.

i yose 21/0/9 coz she needs the dmg boosting early on atleast you get the impaler and the armor runes will keep you safe till then

this i find to be the best combo of health and dmg for riven she is realy hard to kill knowing how she can run in and out of combat and with the impaler her dmg is as good as in any pure ad build witch lacks the force to survive a team fight

Flash And Exhaust are my personal choice ofc you can youse Flash + Sprint witch in any case will help players who arent youse to run with Riven its not as easy as it looks if you are going versus stuners or slowers

DO NOT JUNGLE WITH RIVEN she just not made for it keep it to the lane untill you get madrez then you can go and farm all the buffs you need and ofc solo nuke dragon on lvl 6-7

The best party for riven is a good cc'r like veigar sion and ashe when you have range support + stun or slow you can easyly nuke 2-3 ppl with not so many dmg on you just hit and run thats how riven is played then you can youse sprint and chase the slowed person to his death. Care ALOT early game when ppl will be able to nuke you dont get over yourself i know its temting but dont w8 for impaler + warmorg and then they are all yours

I dont find any cons in Riven but thats me :D