I used ESV for 2 years and with a scale I found it very easy to mix and it worked great in my system. The reason I changed was Marine Depot was out and I got a great deal on 4 beat up boxes of Instant Ocean that had got a little wet at the LFS. The salt was bagged so it was just cosmetic and at $30 per box it was 1/3rd the cost of what I was using. I also was fresh off a Triton Test that showed my tank having elevated Lithium so MD being out and my Triton Test pushed me to try something new. I am happy with the results and the coraline algae has improved with the change, but that could be from pulling bio-pellets offline or just my tank maturing. I am about 12 boxes in since my change from ESV and the savings just bought me a very nice frag pack from Copps
I have never been one to cut corners or go the cheap route and this is why my mind told me that a salt that cost twice as much had to be better? In my experience that is not the case and IO is now my salt of choice. I need to take some pictures to back it up, but I have been waiting for corals to grow in before I show off.