We stayed on the Halki Isles for 14 days (it is just off Rhodes). We chose this island as we wanted to get away frmo it all (and get away we certainly did!!!.
This place is not for everyone, there is very little to do there, but if its peace and relaxation you want...you have got it!
The people there are very friendly, but it is basic...a few tavernas, one taxi for the whole island, a few little market shops, and thats it. There is no bank and there is just one cash machine which doesn't work most of the time. The boat from Rhodes to Halki only goes once a day and doesn't go often, so once you are there you are there!!!
The water is crystal clear (beautiful) and it was very hot when we were there (july). There is a small artificial sandy beach, and 1 or 2 rocky beaches but thats it.
There were no mosquitoes where we stayed (Kaliopi apartments). Our apartments were clean but very very basic, not even air conditioning...but doors could be left open for air to go through.
Food and drink there were cheap (and cigarettes if you smoke), but once again THERE IS VERY LITTLE TO DO.
This suited us perfectly, but for most people a day or 2 would be enough.
Our stay there was pleasant.