Indeed it is better than Scotland in January - probably some 15 degrees better in a bad year! I can vouch for that as I go there every year from GLasgow for three weeks over Christmas and NEw YEar: no contest. THe weather is usually around 18/20 degrees, a bit mixed sometimes, occcasionally cloudy, but you can be really lucky - as I was last year with 19 out of 21 days good weather.
It is difficult to recommend a resort or accomodation without knowing your tastes. Puerto Del Carmen is "young and lively" and not without its share of "tack": the middle part just looks to me like any young resort where large numbers of "Brits" go. Night clubs "british" pubs, cheap eateries etc., at its worst (though the odl town is nice) a sort of Blackpool in the south atlantic. THE beaches look good though and clean I must say.
Costa Teguise is a competely artificial environment without a defined centre, inlined to be a bit quiet.
My ownpreference is for Playa Blanca on the south coast, a very nice upmarket-ish resort attempting to attract quality tourism, and with enough beaches and local restaurants to keep you happy for a fortnight. There is a paricualrly nice hotel called the Rubicon Palace which we once stayed in, a bit out of the town but not that far. Much frequented by Spaniards it has to be said which is usually a good sign. Playa Blanca has two nice villages reasonably close by (ie. a taxi ride) for eateries: Yaiza and Femes, the latter more of a hamlet.
Eric Gray's website at
http://www.graysworld.co.uk will give you a sneak preview of Playa Blanca.
Jaimé