In short
Aswan sits on the Nile at the first cataract, on the historic boundary between Egypt and Nubia. Part of its population is Nubian, with its own language and culture.
The temple of Philae, moved stone by stone to Agilkia island before the High Dam flooded the site, is reached by boat. Abu Simbel is three hours south by road.
What it really costs
Aswan is the cheapest stop on the classic Egyptian circuit. Feluccas and Nubian guesthouses on the west bank cost little.
The temples are each paid separately, and prices have risen sharply in recent years. The boat crossing to Philae or the west bank is added to the ticket.
What nobody tells you
Aswan is markedly calmer than Luxor and Cairo: touting exists but is far less aggressive.
Abu Simbel is done in an organised convoy leaving around three or four in the morning, or by short flight. The road alone takes three hours each way.
Summer is extreme: from May to September temperatures regularly pass forty-five degrees. The usable season runs from November to March.