Typically you get a much smaller number of RSUs than options. Though there's no strike price. So RSUs are often worth more if the stock doesn't move much, but worth a lot less if there is a huge run-up.
The downside is exactly what you say - the potential upside on options is massively greater than RSUs.
If your stock price dips 20%, odds are that most of the stock options you've given out in the last couple of years are now out of the money. But your RSUs retained 80% of their value. 80% of a golden handcuff is a lot better incentive to stay than 0% of one. However Wall St can easily drop your stock price 20% based on nothing real.
On the other hand, if you're issued stock options with a strike price of 10% or so below the market price when they were issued, a 25% drop means that they're completely worthless.