My husband and I stayed in one of the apartments at the resort for a week in mid June 2011.
First the good stuff:
The apartment was fabulous with a large lounge, separate kitchen, good bedroom and big bathroom (with two sinks - yey!) and a balcony which linked the lounge, kitchen and bedroom. There was air conditioning in the room and a tv which had BBC1 and BBC News (but no other UK channels). It was also very nice to have housekeeping services despite being in an apartment.
The pools are fantastic and the one which is for the apartments was pretty quiet when we were there though there were lots of families with young children if that bothers you - we quite like it as it gives you something to watch in the pool! There's a jacuzzi at the end of the pool too. I've read other reviews which say that the pool temperature is cold and it's not hot but actually the weather was so hot it was nice to cool down or to sit on the edge dangling a toe to regulate temperature.
The Hiton facilities are very nice and there are lots of pools in that part of the complex these are probably a bit more aimed at families though. We enjoyed Rubi bar and L'Aquilla poolside restaurant. I note that others have said that the food was very expensive in the hotel. It was, given the weakness of the pound at the moment, but we didn't find restaurants off the resorts any cheaper.
I had a facial in the spa which was wonderful but pricey - though no more than in other hotels of a similar quality.

So for the bad...
It was such a shame that the service we received from the reception was poor. I'd assumed from other Trip Advisor reviews that complimentary water was provided in the apartments - it wasn't - so on the first day we asked where the nearest supermarket was and were directed to one which was a very long walk (approx 25-30mins in the heat) and was all on roads with a heavy camber and no pavements. 3 or 4 days later I spotted one MUCH nearer to the apartments on Rua del U.E.A. (if memory serves) probably about 10-15 mins walk and it was a better supermarket and a better walk.
My husband had only brought an iPad to use for work while we were away and when we asked about wifi were told there was only hard-wired broadband in the apartments, this was very cheap at 5 Euros but totaly useless to us. Again, 3 or 4 days later we noticed someone using a laptop, iPhone and iPad in the Hilton bar and so we asked at the Hilton reception and they told us that they did indeed have wifi. This was more expensive than the broadband (17 Euros I think with a discount for a week) but still would have helped us out had we been told by the reception on the first day. It wouldn't be a problem for us to sit in the bar or by the pool to use it!
In April (2 months before our trip) I booked a three hour golf lesson for my husband and a facial for me at the same time - I did this by contacting the reception at As Cascatas. They told me it was all booked and that the golf was at 10 and my facial at 11. We double checked the timings on the day and my husband left me by the pool while he went for his lesson, only to return with the news that the golf course was closed until 4 days after we returned home! He checked with the reception who sent him to the golf shop to see the professional who was nowhere to be found so no lesson was had. No one contacted us to see if we wanted to rearrange the lesson or offered any apology for what had happened. I arrived for my facial at 11am to be told that this had actually been booked in at 10.00!! luckily there was a free therapist who could do my treatment. It may be that the reception had booked these correctly but told us the incorrect times but still not quite the polish you would like from a 5* resort.
It was also disappointing that the main restaurant in the Hilton was closed during our stay so all that was on offer in the evening was the snacks in the Rubi bar and a buffet meal in another restaurant which we did not try.

Vilamoura Marina
Contrary to most of the reviews I read we found that the walk into the marina was definitely 30mins not 15 or 20 as many people said and we didn't walk slowly! The marina itself was lovely very large - much bigger than I had expected - and it was spotlessly clean as were all of the bars we went into. We went to the Mayflower one evening which was ok but overpriced in my opinion and to a restaurant on the corner of the marina near an Italian restaurant another which was well placed to sit at the water's edge and the food was nice.
Due to the distance and one or two health issues I was experiencing we then chose to stay at the apartment for most of our holiday eating in L'Aquilla at lunch and Rubi in the evening which was lovely. The Hilton staff were very good and attentive and made a mean bloody Mary!
There is a michellen starred restaurant called Willies which is very close to the apartments which we would definitely try next time.

Overall, we had a lovely holiday and the facilities and surroundings were fabulous it was just a shame that the service in the apartments let the place down a little. We will definitely return just a little wiser next time !

I think if you have kids with you and want to go to the beach and eat in quite a bit then a car is a must too.

Brilliant apartments next door to the Hilton but with access to all the Hilton facilities, would highly recommend for a family holiday. There are apartments in the Hilton as well but we would recommend these as a better option. The apartment was of a high standard, very spacious and very well equiped. We also requested a pool side apartment so that we had easy access to the pool, perfect with little ones. We were glad we hired a car to access the marina/beach and supermarket but shuttle bus is available from the Hilton. We would definitely go back.