In my particular case, I had worked in the telecomm industry before and had a good understanding of the alternatives and felt that I understood where things were going and my prediction - still yet to be proven - was that they would win.

But you are right, it is yet another risk. At Twilio, the pay was awful but I felt the longer term risk/reward was worth it.

If I was with $startup and the strike price was $texas-sized, I wouldn't do it while the shares were still illiquid because executing would be so much.