I'm cheap. I buy cheap salt (whatever's available and cheap on boxing day sales or whatever/wherever salt sales) and I use the reef calculators to bring the numbers up to what I want them to be.
I follow Ben's suggestion
http://www.canreef.com/vbulletin/showthread.php?t=26590
I instantly increase Mg by about 200ppm, then Cal by about 100 ppm, then add salt to 1.023. Then I test and bring the alk up to 9-10 at the end. The numbers end up being a little higher than the numbers posted and it doesnt' affect my tanks when the water change is only 10% of the total water volume.
With the above noted method, I had used up 6 buckets of the bad batch of Kent salt, right now I'm using up the 6 replacement buckets of good batch of Kent salt. I've recently bought 10(+1) bags of Oceanpure from Hidden Reef and I'll be using that up next.
I cannot justify spending $90 for a bucket of salt when I'm unable to visually see any side effects of the method I'm using. So for me, its whatever is cheap and available (although cheap does not include the Red Sea Marin brand)