We've been twice in April (haven't been any other month!) and stayed in villas each time. On our first trip the pool was beautifully warm - but we hadn't paid for pool heating. As it was our first trip, we naively thought the warmth of the sun was heating it up. On our return, we found out that the previous guests had paid for pool heating - and no-one had switched it off before our arrival!
On our second trip - we didn't pay for heating, and found the water was definitely on the chilly side. However, we spent very little time in the pool. So little in fact, that it seemed a waste to have paid for a villa with its own pool. On our next trip we are staying in a townhouse with a communal pool at Emerald Island resort - which has turned out to be much cheaper than a villa with private pool.
I guess what I'm trying to say is...If you will definitely use the pool as lot, then it would be worth paying for the heating. You are paying for the pool, so it would be a shame to not be able to fully enjoy it.
Julie