I can only wholeheartedly confirm the positive experiences of the other posters.
Went there for an FAA SE/IR to EASA ME/IR conversion last April-May. Instructors were top-class (IR instructors work for airlines), modern sim, and aircraft are well equipped.
The school kept all their promises; something which was not always the case in my previous flight training. Solvi is indeed a very knowledgeable and meticulous Chief Flight Instructor.
The weather can change rapidly in Iceland, but it was not a factor in my training. I flew a few times in low clouds with light rime ice and somewhat windy conditions, which prepared me well for the skill test (in CAVOK).
The other particular aspect of the flight training was the heavy use of NDBs. The aircraft do not have RMI, only a rotating card ADF, but the instructors teach you how to master NDBs using the available instruments. If you can fly NDB approaches and holds, you will be able to fly any other approach out there.
Apart from the flying, Iceland is a great country with fantastic nature, which offers good opportunities for some sightseeing during the time on the island.
In summary, I highly recommend the school and would go back anytime.