Hydrangeas are rarely or never grafted here in the US. I have yet to run into one. However, some places graft hydrangeas in Canada and then these shrubs get imported into the northern states. There is no hydrangea problem that gets resolved by using grafts so buy whichever you want.

Caution: I recently lost a dwarf 4 year old peach tree that was grafted (the top was a dwarf; the bottom was not); the top died when temps stayed mild during winter and then plunged to 15. Now, the bottom is growing 5' high suckers but, since it is not going to be a dwarf, it will get very tall. I am planning to move it over the winter and see if I get any good peaches out of it too. ;o)) Ha! You know... so at least it is not a complete loss of money ;o) Ha!

Yes, the pruned up method does look good and I'll need to do this for a few of my paniculatas that are beginning to crowd out surrounding plants.