The other relevant point, in favor of RSUs is they usually have a double trigger for settling. One is service time, and the second is an equity event. Which is nice because you basically earn the RSU based on service time, but it doesn't truly settle until there's a liquid market available to dispose enough shares to cover tax liabilities.

This is why you'll see recently IPO'd companies reporting large one-time equity compensation numbers.

edit: s/vesting/settling. I believe "settling" is the term actually used.