Hi Clarey, I think wherever you decide to stay in Arillas you will not be disappointed. We usually stay at the Bardis Sun Studios, (just love our hosts), but we spend quite a lot of time at the Rainbow complex too. As has been said Jimmy and Spiros are great.
We liked Pefkos too, although we only visited it once and have been to Arillas 4 times in the last 3 years. That has to say something.
You mention trips, there are various ones to go on, and at least 2 places in Arillas where you can book them. Coach tours take in Corfu town, the Achillean Palace, Pontikinisi (Mouse Island) Kassiopi, Palaeokastritsa and more. We also took the ferry in 07 to Albania and visited the Butrint ruins.
Alternatively, you could hire a car of course and visit more places. We hired a boat last summer and just loved it!
Hope this helps,
lynn xx