I've always stayed in Comfort Villa's in the past, but I have a weekend booked in two weeks time, where I have an Executive Apartment, so will get to compare. My executive apartment includes daily maid service and towels (though note: towels are not for use at swimming pool).
Comfort villa I stayed in during August (at Longleat) had TV, Microwave, Fridge, Gas Oven (though note that the ovens take ages to get to temperature), Gas Hob.
Pool is included - there are buoyancy jackets for young children, or take/buy armbands. Playgrounds including the indoor one (at Longleat it's to one side of the Sports Cafe)
Restaurant's are not that bad at Longleat. I went a couple of years back just with my mother and we decided to eat out every night. Rajinda Pradesh (Indian) was the best I felt at Longleat - but probably not worth while if you have children with you.
This Summer, I found the children (aged from 3 to 9) all found something they would eat at the Sports Cafe located in the Jardin des Sports. 'Dining In' the new takeaway (well delivery service) was actually reasonable food wise, little pricey compared with my local Chinese but that's to be expected. The menu is a bit limited - but if you fancy an evening in but without needing to cook for adults, you can get food delivered (Italian, Indian, Chinese).
Catering Tip: Take an electric Steamer, ideal for doing lots of Veg. Aim not to use the Oven (as they take so long to heat and cook food) only use it for grilling. Parc Marc has quite of choice these days, so get milk, bread etc daily. Lunches: salad, sandwiches, that kind of thing, buffet style - or if you don't mind burger and chips, eat at the Lagoon Bar (pool cafe).