Don't fear competitors who've raised a lot, unless you can say precisely how all that extra money is going to make them beat you. E.g. if ads are the only way to acquire users, and they can buy all the ads, you're in trouble. But money per se is not dangerous.

Notice there's another side to this coin. If you're fundraising yourself, money per se is not dangerous translates to: money per se is not useful. Unless you can say precisely how all that extra money is going to help you beat competitors, don't raise it.