$150k sales in 6 months for our mobile app. Direct Competitor raised $3.5M. We've had just as many users and volume as them. Should we keep bootstrapping or start seeking for Venture capital?
I wouldn't focus on what your competitors are raising. Sounds like you've kept up with them by bootstrapping with far less capital. Your competitor is now on the hook to make a return on that investment while you still have some freedom.
Bootstrap for as long as you can. However, you also don't want to drive yourself to a point of desperation which will likely get you an unfavorable deal.