I have stayed in a 2 bedroom villa at OKW twice and I've also stayed at the YC. I would definitely choose the OKW 2 bedroom villa..... No doubt.
Reasons:
1. more space
2. more beds
3. more bathrooms
4. more closets
5. more privacy
The rooms at YC really aren't very big. Our family of 4 felt pretty tight with the crib set up. Once you see the 2 bedroom villa at OKW you will FLIP OUT!
The master bedroom is probably the size of the whole room at YC... plus you'll have another bedroom, a living room, a kitchen, a laundry room, 2 bathrooms, a dining area, a huge porch with table and chairs, 3 TV's, jacuzzi.....
You can put the kids to bed at night and have the rest of the villa to yourself... you don't have to worry about waking them, you can watch TV, sit outside, cook food, fire up the jacuzzi, etc.
You won't need concierge because you'll have a full kitchen right there whenever you need a snack or drink.
To me it's a no brainer.