[caseysoftware]

Generally, stock options are granted before the company is liquid (aka pre-IPO) and you pay $X with the hope that they're worth more and liquid someday. As you hit vesting dates, you can purchase more of them up to your total grant. (There's also stuff around early exercise, don't worry about that.)

RSUs are just shares you don't own yet. When you hit your vesting dates, you don't have to DO anything, they just become yours. You don't have to pay anything to execute and often the company will sell some for you to pay the taxes on them.

I wouldn't say one is definitively better.. there are tradeoffs:

RSUs can be better because you don't have to spend money to get them and they're liquid immediately (or at least soon).

Stock options can be better because your pre-IPO price may be better than the public price but you have no guarantee they'll ever be liquid.