Came here to do drive-by gloating; see other people already took care of it.
People on Blue side see more of Purple than vice versa. I made a grafick the last time this came up:
Blue sees somewhere in the neighborhood of 12% more of Purple in a typical scenario situation.
In DOTA2, it's about 7%.
Radiant and Dire sides also aren't symmetric across the river, and the differences are far more significant than Purple vs Blue.
Radiant:
Better Mid Block
Accessible jungle camps near mid
Camera advantage
Dire:
Safer Jungle overall (resistant to warding)
Better access to rosh
Bot ancient farming
In practice, Radiant actually has a huge advantage over Dire, but only in the early game. As the game approaches 45 minutes, Dire gets better and better due to Rosh access. The win rates fortunately average out to the neighborhood of 1:1, so no one really complains.