Ripple does outperform Ethereum in terms of market share, but they are very different:
- Ripple is centralized — at least for supply.
- Ethereum is decentralized.
- Ethereum can be mined.
- Ripple is a fixed supply — but Ripple Labs holds uncirculated Ripple in escrow.
- Ethereum on Coinbase.
Besides that they have their respective sectors so they will not compete, so don't be afraid to invest in one of them, because their prices I don't think will affect each other.