+1 on the yes!
My experience with employer share options was via a Save as You Earn scheme in the UK. I signed up to invest 15,000 pounds (about $25,000) over 5 years in Feb 2007 at 54 pence/share. Later that same year, the company went public. Two years later, I could have chosen to walk away with what I had put in up to that point, so about 6,000 pounds, but I held on until maturity.
On 1st May 2012, I collected my 33,000 share. With the shares trading at around 6 pounds, my total holding was worth just shy of 200,000 pounds (around $300,000 at that point!). I've since sold out between 9 and 10 pounds a share and paid for a shiny new fancypants house (arguably this deserves a face-punch), but we signed the contracts before I found MMM!
Obviously what you get back depends on how your company's share perform but, unsurprisingly, I'm very keen on stock options and if I were you I would seriously consider doing whatever it takes to hang on to them!