The location is as "advertised" in the apartment's name: Anticaglia and in the description (Decumano Superiore). (The Roman theatre is on the opposite side of the street but not something you can see). As such it affords easy access to the sights in what was the old Greek/Roman city e.g. Vieled Christ. The Metro is close by; whilst Porta Nolan for Pompeii (don't go to Garibaldi), Centrale for e.g. Paestum or Montesanto station for e.g. Baia are just over 1km away. And if you want to avoid public transport it is possible to walk to Toledo, Piazza Plebiscito etc. or even the airport (4km).
Access is from a courtyard (having passed through a door on the street) going up the stairs shown in one of the photographs. Noise and location are always a trade off. Overall this is a pretty quiet apartment. There are very few people on the street outside. There is very little noise (almost none) from other apartments in the building the apartment is in (thick walls). Whilst there is some - occasional - traffic noise its mainly at the weekend (we stayed 10 nights) and with the courtyard and the apartment being at the "back" of the building away from the street any noise was always "at a distance". You can sleep with the bedroom window open (it has lockable steel shutters).
within a few minutes (say 3-5) there are two supermarkets within a few minutes (a Carrefour and a Deco) making it easy to pick things up on your way back to the apartment after sightseeing as well as Sorbillo's and Matteo's for take out or dine in. Many other well known places to eat within 1km as well.
The apartment itself is very clean and its layout makes it easy for someone wants to rest in the bedroom whilst someone else has a drink, reads etc. In addition to the bedroom window the apartment has two small windows that open onto the staircase that continues upwards and a roof window in the storage room off from the bathroom. So whilst its not a "sun filled" apartment its not "dark" and has external ventilation as well as the air conditioning. Overall the facilities offered are solid.
We let Simone E Laura know when to expect us once we left the airport and they were waiting for us when we arrived. Check in was fast and efficient and they left us with a telephone number to contact them if needed. They were friendly.