All of the salts will work just fine for almost any hobbiest. I have used IO for years. Hawaiian Marine's Weigants salt for about a year with great results but I was never WOWed by it. I used Oceanic's salt for 2 years and must say that it is very cost effective and consistant in its values. Although its values do leave some to be desired ( KH 8, Ca 390-400).
I have been a TM nazi for about a year and it is a good salt, but expensive.
These high-end salts cost extra money because they have extra trace elements and Mg. in them. And TM doesn't really have that much higher Mg than the others, so is it worth it? (rhetorical?)
But the real question is; Does every hobbiest really NEED these "better" salts. I mean to say, is your tank running so perfectly and so close to the pinnacle of peak health and coral growth that you require these extra elements. I think most of us would answer no.
Tropic marin boasts that it has all 70 trace metals in its salt. And obviously some amount of all of these is needed, but why should we pay and extra $10-15 for the extra 5ppm of Boron or manganese if 1ppm is sufficient?
Salt has become kind of a status thing amongst many of the advanced reefers. I mean some people are using Tm pro that aren't even running a calcium reactor.
My message for newer reefers, or non SPS keepers is; use what is available and cost effective, there is nothing magic in the more expensive ones.