We booked a villa (no 6) for a two week stay and thoroughly enjoyed staying here.
The villas are serviced regularly and efficiently. They have ceiling fans and air conditioning (though the latter is at additional cost) - we did not use the air con and and had no trouble sleeping. They are fully equipped with cutlery, plates, cooking equipment, fridge/freezer, microwave, cooker.
Guest Services are on site and I recommend using them - they offer advice and can sell you excursions (but do not do so by ramming trips down your throat). They can sort out taxis, car hire, restaurant bookings and water taxis. Nigella was a star :)
If you hire a car, it is parked across the bay in the village car park.
The villas sit on the north side of the bay and can only be reached by using a 24 hour passenger ferry from the other side. We used this most days and only once suffered a long wait (that was at 05:00 in the morning when the ferryman was reluctant to get up).
There is a funicular railway which you can use to reach the villas and it is easy to use and worked the entire time we were there.
We spent many an hour on the villa verandah watching yachts coming and going. As for birds, it's easy, we saw many - including the St Lucia Oriole, an endemic species. If you like birdwatching these villas come highly recommended.
Marigot Bay can be lively but not too the extent that you need ear plugs :)
There is a good choice of restaurants all within minutes journey.
Great place to holiday.