We stayed for 2 weeks in April, family of 4, with 2 daughters aged 4 and 7. Roy was very helpful prior to our trip, providing contacts for airport transfers and car hire, and information about the island (shops, restaurants etc).
The hotel is really good - our kids loved the waterslides, pools and the playground, and also had fun at the kids club. Pools are good with plenty of sunbeds - although towels were a little scarce! We had a lovely day on a "Bali Bed" on the beach - with fruit and prosecco included for €25.
The vast majority of guests at the hotel are all-inclusive but we didn't find it particularly difficult getting meals / drinks etc. Breakfast at the main buffet was €24 per adult and the kids were free - dinner was €50 per adult and again kids were free. We also ate in one of the other restaurants a couple of times - each restaurant has both a small buffet / walk up station (eg pasta bar) and a la carte - there is a price for the buffet and a priced a la carte menu if you ask - we ended up just having the buffet and it was €25 per adult - again kids were free. Drinks at the bars during the day were €2 for a bottle of water or a glass of coke. We decided not to bother with any days all-inclusive - the price would have been €65 per adult and €33 per child per day.
Santa Maria is a lovely town, either €3 taxi ride (€4 at night) or about 30 minute walk. There are lots of good restaurants and we ended up eating in town most nights - we didn't have a bad meal at all. We tested the tuna tartar in most restaurants and decided the best was in Angela's, a restaurant on the front, just along from the pier!
There is only one supermarket in town - we didn't actually cook in the apartment, and only ever ate breakfast there (cereal and toast) so can't really comment on how easy self-catering would be - but there did seem to be a selection of basics.
Amy at "Surf Hub" was really helpful with car hire and other outings - we had a car for a day and did a tour of the island - salt mines were great viewed from the top of the hill (we didn't go in), the blue eye was good - best bit was the natural pool. We also did a half day sailing trip with some snorkeling, the kids had a body board for a few days and my husband had kite surfing lessons which he loved - all arranged for us by Amy.
In summary - a fantastic 2 week break, perfect apartment and hotel, and I would definitely recommend exploring the town and island.