Depends where you want to stay - if you are looking at south Tenerife the Spring Group of hotels are a good standard - the Bitacora in central Las Americas is consistently praised, or if you want Los Cristianos they also own the Arona Gran hotel.
The Gran Tinerfe hotel at the other end of Las Americas is very good also.Almost sure you can choose AI at all of them.

The RIU Vistamar is an exceptionally good hotel and of a very high standard!!!! Unfortunately the RIU Buenavista in Tenerife is not a patch on the Vistamar!! And the BuenaVista is in the middle of nowhere.

The Jardines del Teide is excellent, although I obviously haven;t sampled every single AI hotel on the island.

Bit of a catch 22 with all-incs in Tenerife, as the best two are the Roca Nivaria and Bahia Principe but they are both located in "the middle of nowhere" also known as Playa Paraiso.

The Luabay Costa Los Gigantes is meant to be good but I think it's changing to a Holiday Village next year and not sure how that will pan out.

Otherwise, as mentioned, there are several good hotels in PDLA that offer an all-inc option, but with mixed boards you often read of the all-inc guests being treated a bit second class. I guess if you're all-inc at a bar and the guy next to you on half board is waving his Euros, you know who's going to get served first !