I wouldn't go as far to say that generic drugs and store branded vitamins are garbage. The big chains use the same well known companies to make their generic brands and the big chains go through great efforts to make sure their stuff is as claimed on the bottle. The last thing they want is a multi million dollar lawsuit on their hands. I recently read an article in the WSJ that says GNC is now testing every single product they carry in their stores to make sure the ingredient claims are correct.
With regards to vitamin timing, it really make no difference. The problem I have with most multi's is they suck. Many contain elements that inhibit the absorbtion of others. So I personally don't use multi's anymore...I use individual vitamins as needed and things I know most people tend to be deficient in. Starting with: Vitamin D, Zinc, Magnesium, and Selenium.