Basically all early stage startups use ISOs. Public companies typically use RSUs. Some startups transition to RSUs before their IPO.
RSUs are kind of unworkable if the valuation will increase significantly before the shares become liquid since you owe taxes on their value as they vest whereas ISOs let you defer taxes until at least exercise if not sale.
RSUs are kind of unworkable if the valuation will increase significantly before the shares become liquid since you owe taxes on their value as they vest whereas ISOs let you defer taxes until at least exercise if not sale.