I encourage you to do your own research, but the general rule of thumb is you will make more money working for an established tech company even if you do pick a unicorn. Since most of the data I have for this isn't public I couldn't share it if I wanted to, but in addition to all of the public data you can Google I personally know about a dozen people who were employee #X (X is a single digit number) at companies that were acquired for more than their last valuation at over $1 billion and only 1/4 of them actually felt like it was good financial ROI.