Gutters are the functional part of your house and you don’t want to accent them in any way. Match the gutters to whatever color is behind them. If the gutters run along the trim, match the gutters to the trim color so the gutters disappear. If a gutter runs along the house, then match the gutter to the house color. That way the gutters will not be the first things you notice from the street.
Just like metal roofs, however, there are some fancy gutter materials like copper that will stand out against any trim and will become a design feature of your house. Just something to keep in mind.
thanks for the the comme nt it does make sense. doris