I've kept them, and they are beauties. The first time I bought a group they brought Ich in for the first time in many years, but I cured it and added to the group, and they were lively fish.
The reputation as nippers is the result of us doing things wrong. Ideally, they should be in groups, but how you keep those groups matters. If the water in your tank moves around with a good current, they'll thrive. In slow tanks, they get bored.
A lot of bright silvery social fish have sunlight and ripples as camouflage, and very active lifestyles that can twist into nipping if they are bored, or if the tank set up doesn't let them burn off energy in fast water.
With accidental arrivals, you can stuck. There's only so much space. If you can easily fit more and don't have fancy guppies, Bettas or other 'freak-fin" fish, I would do it. They are great in groups. But there should be surface current, and a large enough tanks (30 gallon plus) for them to frolic.