All that I've ever used for grafting is water sprouts. I also do my grafting mostly onto water sprouts as usually I'm turning varieties over to other varieties. I let the grafts grow straight up for a couple years and then bend them in the direction I want my new scaffold. Either that or I graft onto a water sprout on the trunk and turn the tree into the new variety from that point creating a new central leader. Cleft grafts are too gruesome and time consuming, not to mention 3 years of ugly.
Anyone suggesting a problem with water-sprouts is talking about something I can't imagine. The wood itself can sometimes have incompletely formed buds which is best to avoid, but those are usually towards the base.
[NAFEX] water sprouts for scion wood,
Alan Haigh, 02/05/2010