The thing is, in today's environment you can almost certainly get more cash comp at another company, almost no matter where you are. The stock can hold you back. The new company will probably give you more, but there will be a cliff. Often you can negotiate for something like giving you the stock money you'd get in the next 6 months as a hire on bonus.

If you worked at a company for a few years and they went ipo, that's a different situation.