I was there for 2 weeks in January. It’s absolutely stunning. The reason why few people visit is because there are not many flights going there otherwise it would be another Seychelles, Mauritius, etc. Everyone should go now as in five years time it will be a completely different story as they just got fund from World Bank to develop tourist infrastructure.
There are also not many luxury hotels, apart from Principe. I would avoid Belo Monte Hotel on Principe. Absolutely don’t care about customers at all. Stay at Sundy, Makaira or better Bom Bom if you can afford and just visit Praia Banana.
A rent a car is a must. It is very safe to drive though, even at night. All the reviews are a bit outdated as there is a new road going from the capital to Cao Grande. After that it is tricky and you need to be careful as the roads become worse and worse. But the beaches in the South are to die for. The best of all, we were sometimes the only ones on the beach. Unless it’s a holiday or Sunday, they are practically deserted.
I actually liked the Sao Tome island more, but that is probably more because we were stuck at Belo Monte due to hotel’s terrible management.
I am in the process of writing a trip report. Another thing - Don’t rely on the Bradt guide.
For more info, PM me.