I've been to Corralejo, on the northern tip of the island.
It's constantly windy, which sounds like a pain but due to the heat it's nice and cooling. When we went in July there was a hell of a lot of empty buildings due to the economy falling, which was a shame to see, but there were still a few decent restaurants etc. as you say it's just a 'cheap and cheerful' place.
If you're up on the north side, go for a walk late evening on the sand dunes and possibly the Isla de Lobos - they're really nice, apart from that - there really isn't a great deal to do