I went to Blue Bay Escape last year in August and was very happy with it. Our room was on the ground floor which was alright though the sea views are very nice as you can see great views of Albania apparantly.
I think the weather is as good as it is in August in September.
Worst thing about Corfu in general is their airport is the worst.
Baggage reclaim is rubbish as there are 2 carousels and they break down every 2 minutes but other than that it was great.