Overall, our stay at the Louis Studios in Santorini was excellent. For ease of reading, I'll break this review down into 'Pros' and 'Suggested Improvements' (although in fairness, there aren't many of the latter).
Pros:
Location is VERY close to the airport, about 5 minutes drive. On our arrival, Dimitri was there waiting for us and took us back to the appartments (His father Nicholas usually does the driving, but was on another airport run at the time). It's worth pointing out that the close proximity to the airport did mean that we could hear planes taking off and landing, but they weren't loud or disruptive at all.
Check-in was quick and thorough, with Dimitri giving us a good tour of the room and facilities. He also took some time to suggest some local restaurants and places to visit on the island. Car rental, bus and taxi details were provided.
The room was immaculately kept, with a (very friendly) cleaner visiting each day. The room was air-conditioned, keeping us cool at night and had shutters that allowed you to block out the sun at night whilst keeping an airflow.
We had 2 small issues on arrival (a broken balcony chair and a safe that needed new batteries) - Both were resolved within about 30 mins of reporting them.
The local minimarket is great, stocking pretty much all of the essentials that you could need. A word to other travllers; use common sense. Anything imported was very expensive (Think £5 for a box of Kelloggs). But if you buy smart you can get things like freshly baked bread, jam etc for a couple of euros and make your own breakfasts and lunches. The rooms had facilities to allow you to do this.
The pool area was also spotless, and we never struggled for space.
Nicholas is generally happy to drop people into nearby Kamari each evening and pick them up so long as not too late (10:30). He even (very kindly) took us to Thira once when the local bus service let us down (we waited at the nearby stop for over an hour for a bus that never arrived). A lovely, friendly chap.
Suggested Improvements:
Whilst we didn't go on holiday to watch TV, the one in the room would have been used had it offered channels other than Greek. As such it remained off the entire time. A cheap alternative (if you don't want to change satellite packages) might be to put something like Chromecasts or Apple TVs in the rooms? Would give people the ability to beam their ipad/iphone content on to the screens if they were planning a night-in or wanted to relax away from the pool.
A toaster would be a low-cost improvement to the kitchenette area, even if it had to live in one of the cupboards when not in use. We didn't use the hot-plates, but would have used a toaster every day.