Plug-in trimmers account for the most sales, since they're relatively light, quiet, and inexpensive, start with push-button ease, produce no exhaust emissions, and require little maintenance. The best also perform comparably to petrol-powered models. But you'll have to work within range of a power outlet and be careful not to cut the cord.
Landscapers favour these for their power and mobility. But petrol models typically weigh more than electrics, and their two-stroke engines require fuel mixing, pull-starting, maintenance. They are usually more expensive.