Well, you can still purify water with them.
In my experiance with 1 oz Maples over a 10 year period, I have found that the milk spots appeared after the transition to tubes only. Thousands of Ag maples in sheets w/o a single milk spot. 88/89 Ag Maples were issued in a thicker plastic which usually yeilded some toning w/o milk spots.
From my experience with Ag maples concerning the numismatics side I found that the 1997 key date coins (low mintage) and NGC/PCGS Ms70 rated are the popular choice. Even the proof issue from 99' is nice.
Coin Population is important when veiwing the different variables on Numismatic Value.