Sure it's a unique place with the islands having the history that they do, volcanoes and all. I'd however wager that Iceland is a far more unique place than the Canary. The islands are somewhat "old" now and if you went there, most likely would end up in Gran Canaria and that's like Spain at sea. Being out in the deep Atlantic however will make warmth that much enjoyable. Did have 40C there one day and barely even noticed it at all. A place where the variables work together for a rather pleasant experience. You can take trips into some parts of the jungles there and even take a trip up one of the volcanoes with a guide. Cost some but if volcanoes is one of the reasons you'd visit then likely worth it. On all the islands people are incredibly relaxed and really helpful so genuinly a nice place to relax.