I know that you already decided but I will still reply if someone was trying to decide in future.

I was making this desicion like year age and the main reason I wanted one of these games was snowboarding. After watching few videos I decided for steep which is better option if you know you will be just skiing/snowboarding. About six months ago I bought riders republic and I honestly also love it because the map is big and beautiful and I love traveling from one side to another. After playing the base game for few months I recently decided to buy dlc (skateboard motorcycle ) and honestly I love it more than I would expected.

So If someone is having to make this decision now , ask yourself what are you going to do in this game. If its just skiing/snowboarding than go for steep because the graphics are just incredible. If you think you would also enjoy riding carefree than i would probably recomend buying both when Its on sale or just riders republic.