Maid service is provided either two, five or seven times a week. Most apartment buildings have a 24-hour concierge desk. While some apartments do have restaurants and room service, the majority do not. That is how they keep their overheads low and charge less for the room. Yes, possibly even more so than a hotel.
Most apartments buildings have discreet entrance areas.
The other guests are less transient than hotel guests, and, hence, the receptionist tends to recognise you by face. Most apartments have video entry phones should you have guests. With the increase of lone women travellers safety is recognised as an important issue. Most apartments do need to be prepaid. Your local apartment service office or travel agent can take care of the details and ensure you know the exact procedure at the time of enquiry.