The 2 bed/2 bathroom apartment itself was great with everything we needed (kettle, dishwasher, soap, toilet roll, towels, clean bed linen, TV, settee, fridge and all utensils), a great layout and with the added bonus of a balcony looking towards the cathedral. It was clean and self check in/checkout was smooth and easy.
The location was OK, and was close to bus stop 13 for tour pickup/dropoff. You can walk to the cathedral in 10 and the rainbow street in 15 minutes. Walking to the old docks for boat tours/Lava Show took 35 minutes.
The main issue for us was not being able to sleep until gone midnight. There were people in neighbouring apartments and we could hear them talking like they were in the next room, and from above and below, whenever anyone moved a chair or table it was loud as if it were in the apartment. This may not be an issue if you're a heavy sleeper.
The other minor issue was the mixer taps did not give cold drinking water (kitchen and main bathroom) even when on cold, the water was always slightly warm sulphur smelling. This is unlike the 3 other places we stayed on our Iceland trip, where the water was odour free and totally drinkable. There is a shop 3 minutes walk away to buy bottled water, so that made life easier.
If you sleep regardless of noise, are happy with bottled drinking water and don't mind walking for food and attractions, this place is a great place to base yourself. If any of those things bother you, consider it carefully before booking.