In reply to Owldog1:
I was just there over New year.
Tenerife - escalada deportiva is the most up to date one I know and can be got from the climbing shop in Arico. They sell them and also hire it (only 5 euro for your whole trip). Would echo a lot of what Najki_2000 said, I also stayed in Granadilla and Arico might be better. On the other hand its only about 30 mins drive and Granadilla has more shops etc. You could also easily stay on the coast as all the mountain villages are accessible quite fast from the ring road.
The Tenerife article sums up the crags well, my few extra thoughts would be;
Arico - most extensive and the choice of sun or shade in the day is nice. Good abrasive rock. A number of the routes short but plenty up to c20m as well.
Guaria - I thought the best crag on the island. Long routes and generally decent rock. Very hot though, even in early Jan it was a bit warm with no cloud.
Canades (volcano) - the rock type is fun but its a bit of a pain to find routes and wasn't super impressed by the climbing. Would definitely spend at least 1 day there though as its beautiful.
El Rio - Lovely long slab routes in the main crag although again hot. The shadier harder bit (Zona Zero) was also good.
Overall I though great place for a winter trip, pretty cheap away from the tourist spots, easy to get around, good climbing and good weather.