I'm very confused. Are you staying 4 or 5 nights? I can't seem to figure out what size villa you are pricing. If it's anything bigger than a studio (and those can't sleep five), there's no comparison between a regular room and a villa. The villas have at least two bathrooms, a jacuzzi tub, walk in shower and laundry facilities. Even if you don't use the kitchen, you have two TVs and a TON more space. Also there are no "room" taxes for the Villas (which could be a couple hundred dollars on the price of room you are talking about), not to mention "self parking" is free (again $20 per night adds up).
Just sayin'

there's a lot of hidden fees that should be considered. Plus your family's comfort and personal space. Besides the Villas can also be much quieter with less traffic. Granted you don't get maid service every day, but you can wash your towels and have clean ones every day.
It's certainly up to you. However there is that thing once you stay in the Villas you won't want to stay anywhere else!