Grafting - how does the rootstock affect the grafted tree

[Taylog1]

I found a nice apple tree in the wild whose apples are happily still on the tree in February (I'm in Dorset UK), firm and sweet. 

I grafted some cuttings into MM106 rootstock last year, all took nicely - but it just occurred to me, is it likely that the ripening characteristics of the rootstock will affect the tree, or is it just the height/vigour that's affected ?

Gareth