I don't dislike 90% per se, and I used to love finding it at face value when I was into CRHing. But I know from talking to some old timer coin dealers that back in the 80s when silver was shooting up to 50, the coin dealers were not paying anywhere near melt for 90% because so much was being dumped on them by sellers due to the quick rise in price and refiners had too much so they weren't paying the coin dealers much for it. One told me the most he remembered paying for it was 36 bucks per ounce. That's a big haircut when silver was near 50 for at least a while.
So when I can get .999 at a better price based on local buy/sell spreads it is a no brainer for me to get the .999 over 90%. I believe that if/when silver does take off past 50, we will see pretty much the remaining junk silver and silverware get sold that is now being held by non silver bug types who are holding grandpas coin collection, etc, for sentimental reasons. By the time we get to that silver price, many folks will need the cash so when they see the price get that high and hear about it on TV, they will sell I believe. At that point it will be mostly the PM bugs holding their metals waiting for 100 bucks, don't know if we will ever get that or not.
Since I don't know when I would sell a bunch of my silver (50, 60, 70, ??), I want to be able to get the most I can when I sell, and I believe I will be able to do that with .999 over junk. I still have some junk silver from my CRHing days and from my early days as a silver bug when I was buying that exclusively.
Another problem with alot of the junk silver is that it is highly worn. I believe that when silver takes off in price, junk will start being bought by weight and not face. When that happens, those who invested in worn liberty quarters, Walker halves, mercs, etc, may have an unpleasant surprise when they sell.
I would really like to get cheapo silver dollars, but even with the good coin dealers I buy from now they want way too much premium even for lower quality coins based on melt. If they ever sell these at melt or below like the halves, etc, I would buy a bunch of the silver dollars simply because they are cool. These coins have the widest buy/sell spread for any common form of silver coins I see around here.
Jim