Correct me, if I'm wrong:
Ripple was developped and held (50%) by a company, wasn't it?
In this case I absolutely prefer bitcoin.
Are there some control mechanism to prevent price manipulation by their own company?
You're talking about the currency inside the Ripple payment system, often called XRP. That's really not intended to be used as a means of exchange or a store of value (at least in the near term), so it's not really fair to compare it to Bitcoin (which is).