Quick answer
Roswell is the more historic, walkable choice — prized for its Canton Street district and Chattahoochee River parks, with median home values roughly $567,000–$678,000. Johns Creek is newer, more affluent, and more residential — known for gated golf communities and some of the state's highest-ranked schools, with home values around $679,000 and a median income near $157,000. Both are Fulton County, car-dependent, with a 7.75% sales tax. Choose Roswell for historic charm and the river; Johns Creek for large homes and top schools.