Chainsaws scare the **** out of me. Hire someone unless you plan on cutting wood every year.
Sure, but last week's sad events (6 year old in Salem, elderly Newington guy) tragically proved neither professional tree removal companies nor individual tree cutters are accident proof. Is there an absolute guarantee a professional tree removal company's current employees know what they're doing, they're adequately insured, their contract's worth anything (if one exists), etc.? Sometimes, but there's usually a benefit/risk/cost trade off. Even with a boat load of company, homeowner's or umbrella policy coverage, no guarantees exist preventing a tree or large branch from falling in an unplanned direction.