For me, I don't care about per cent, I care about what is out of my pocket.....for example, some kids may be better off with academic & merit scholarships than athletic scholarships.
I think a "good offer" is a very relative term. It is relative to only those schools an individual is looking at at that particular point in time....kind of like economics 101 with supply/demand pricing. It seems pitchers get the majority of the money. When you start mixing public and private schools, then I think it gets down to the nitty gritty because you have to prioritize what is important to you (as TRHit suggests above).