Be careful executing your options if you don't trust the company. Execution might not substantially improve your rights as a shareholder. It will, on the other hand, involve you surrendering your own cash. There are startup horror stories of early employees executing and getting zeroed out at acquisition.
(I say this as someone who listened to those horror stories, refused to execute options, and lost a low six figure return as a result. I don't regret the decision though; on the other hand, if I had ponied up thousands of dollars and gotten zeroed out, I probably wouldn't be able to live with it.)
I know of multiple startups where the acquisition price was exactly the price necessary -- down to four significant digits -- to pay off the VC companies that made up 3 of the 5 sitting board seats.
I myself exercised a (small!) amount in a company that got acquired and my shares all went to $0 because other shareholders got preferential treatment. (This company earlier made a point of the fact that there were no investors with preferential treatment, but either lied about that or somewhere along the line they got desperate and gave preferential treatment. In either case, the stakes were too small to bother suing.) At least I could claim a capital loss.
Let's say you raise $10m in preferred rounds and proceed for a few years, but it's not working. You eventually find a buyer that will acquire/acqui-hire your company for $5m.
That $5m is not split evenly, it's distributed to the highest priority share classes first (after potentially paying off certain debts, notes, etc). So your Seed, Series A, etc will get paid out of the $5m – nothing is left for common.
Common is the last to earn money, and options are part of the common class.
(I say this as someone who listened to those horror stories, refused to execute options, and lost a low six figure return as a result. I don't regret the decision though; on the other hand, if I had ponied up thousands of dollars and gotten zeroed out, I probably wouldn't be able to live with it.)