Completing = winning. You need to beat the NPC, but you can try again until you beat it. Once you get the hang of the track, you'll end up beating the NPC each time by a longshot (tip: jump or roll to stop yourself from sliding). The PvP race has separate rewards for placing and participating.
Many more attempts and still failed every time...
I guess I just feel a bit let down as I was expecting a "gift" from Cryptic, but instead I've been given yet more grind...
in regards to the snowball piles not giving snowballs for some players,
I noticed that if you don't have any snowballs currently in a device slot, they automatically go into your inventory. I am wondering if that is what is happening with others. Since I haven't had any problems getting snowballs (once I discovered where they were)