My kids go to Wyngate but I have a good friend that started in K using the before/after care on site at Ashburton and I picked her DD up a couple of times to take to gymnastics. It seemed like a nice environment for high energy kids. If your child is more introverted and needs more down time, I would really look into a babysitter or au pair. I just think it is a VERY long day for some of these little ones. I know other families who use Wyngate/Ashburton aftercare that are also happy.
http://www.mccaedu.org/centers/ashburton.html. I think both these places are likely to fill up, so I'd get on their waitlists very soon.
FYI-- I know several families who have chosen to take their kids out of these aftercare centers (more specifically the YMCA) to avoid behavior problems. If you have multiple kids and are ultimately paying for 2 kids after and before care, you might do better to get a babysitter at some point. A babysitter has the added benefit that he/she can take your kids to soccer practice and get homework done before you come home from work. By third grade, you've got some serious homework to deal with. . . so just keep that in mind going forward.
I think kids needs change over time, so I suggest keeping a willingness to change your arrangements as the cirucmstances dictate.