Percentage figures are also worthless, unless (A) there's only a single class of shares, or (B) you know all the financial terms (liquidation preferences etc.) attached to each class of shares.
EDIT: I just noticed that OP was talking about options (not shares, as I had assumed). So, of course, strike price, vesting period, and vesting cliff are also important. When presenting the offer, the company may justify the strike price based on the valuation of the company at the last funding round. However, this valuation is often an overestimate, as they're based on the value of just one class of share, rather than the actual mix.
Percentage figures are also worthless, unless (A) there's only a single class of shares, or (B) you know all the financial terms (liquidation preferences etc.) attached to each class of shares.
EDIT: I just noticed that OP was talking about options (not shares, as I had assumed). So, of course, strike price, vesting period, and vesting cliff are also important. When presenting the offer, the company may justify the strike price based on the valuation of the company at the last funding round. However, this valuation is often an overestimate, as they're based on the value of just one class of share, rather than the actual mix.