Marconi Plaza area is nice and definitely safer than a lot of other neighborhoods in South Philly. Central South and East Oregon both sound like made up realtor neighborhood names because those are general locations. The area north of Oregon Ave is called Lower Moyamensing. I would avoid the entire stretch from 8th St to Front St. 9th St to 11th St is decent and 12th St to Broad St is the nicest part of that area. South of Oregon Ave is similar but that area is called the Stadium District. Proximity to Broad Street is key if you want to use the subway.