I think of the resorts in Tenerife going clockwise from Tenerife south airport. The first resorts you hit are the original ones from when Tenerife was developed for tourists. The tourists have left those resorts now and it's the Spanish workers who tend to live there. There's still some expat bars though, but it's all very much run down and 60s shopping precinct style. (Costa Silencio).
Then you move round to Los Christianos and Las Americas which is very touristy, and built up, again lots of shopping precinct type places, bars serving beer and all day breakfasts, macdonalds, fake sunglasses sellers, discos, young crowd looking for cheap holiday in the sun. The beach there is huge and family friendly, and the sand is imported so it's golden sand rather than the natural volcanic black sand on natural beaches on Tenerife. I've stayed there for the beach with young kids, but it's not pretty in my opinion.
Adeje is more upmarket, especially as you move northwards. Much smaller resorts and with that, less choice of bars/restaurants. There are some lovely smaller beaches, though.
Los Gigantes is the resort before the imposing cliffs take over the coastline. Los gigantes (the name of the cliffs) is a bustling harbour town, still quite touristy with loads of bars and restaurants on the marina, but the scenery is lovely. The towns across the north coast and round to the capital, Santa Cruz are less tourist resorts, more original towns.
Tenerife is obviously a volcanic island, and it is beautiful, but not in a verdant, lush way. A trip up to El Teide is a must - it's like going to a different planet. Tenerife a great place for boat trips and dolphin/whale watching. There's great walks (if you like hills). There's beautiful villages as you go up the volcano (if you like hairpin mountain roads). I'm not a fan of massive resorts full of British people (no offence to Brits, I'm one, but I like to go on holiday to experience something else). In Tenerife there's plenty of massive resorts but it's also possible to stay clear of all that. I liked the variety of things on offer - days on the beach if we wanted, trips to water parks for the kids but also going for lunch in a small village up the volcano, boat trips around the north coast etc. You need to hire a car and get around the island,