Enzo's room was a delight to stay in. The bed's comfy, the decor modern, and the bathroom sparkling. Maria, his sister, does most of the hosting and maintenance. She's hospitable and welcoming, as is Enzo - he's really cool to talk to, when he's not traveling or doing work abroad.
Portuense is out of the way w/r/t Rome's main sights, but buses to Trastevere, Testaccio, and Ostiense is frequent and reliable. For neighborhoods further afield, you're going to have to walk to the Metro Station at Basilica San Paolo about 2/3 of a mile away (nice walk, though). Be aware of the distance involved in traveling from Enzo's - otherwise, his place has my highest recommendation.