We went a couple of years ago, always wanted to since a novel I read as a kid … Hammond Innes/Douglas Reeman type thing set in Iceland.
Reykjavik is smaller than you may think but a couple of days gives time to see the blue pool, a big waterfalls & tectonic plates splitting & geysers etc.
I think its the kind of place for a long weekend or a good few weeks when you can go around the rest of it.
Glad I went except for asking mrs geejay to move in with me when there & ordering a double brandy to celebrate …. she is doing fine, the brandy nearly broke me … still should be better now.