It used to be PCGS's as they are/seem sturdier to me and seem to hold up better over time and from scratches but I do like the newer edge views so that is a tie now As for ANAC's having the label on the tops that is so nice when you have alot to store and not having to keep lifting them up to see which one it is. They should all use that feature.
Compugrade It is small like the old ANACS slab but slightly thicker. They used a denser plastic so it feels solid and substantial in your hand. The plastic was very clear and the edge of the coin could be seen almost all the way around (This was in 1991, eight YEARS before the NGC edgeviews, and eighteen years before they became commonplace.) and it had a top of the slab label so you could tell what was in the slab without having to take it out of the box. (Seven years before SEGS did it and fourteen years before ANACS did it.)
While most of my slabbed coins are PCGS, I think the NGC slabs have a better appearance. I have little experience with slabbed notes. I recently purchases my first and only, a Series 541 $1 MPC, it's in a PCGS holder. So I'll say PCGS for notes.