SALT for a reef tank...

Instant Ocean has always worked perfectly fine for me. The reef crystals have some added nutrients in them.

presently I am using kent, I have used instant ocean and red sea

I am having no problems with kent products its dissolves easy and is affordable, but then again I have decided that I would dispense with trying to do a bunch of corals and have basically gone fish and rocks and whatever soft corals will live in my tanks.

Mushrooms are not only living but multiplying, and my trigger makes short work of other types of corals.

Just me personally, but I have never found that "perfect salt". I prefer Ocean Pure Pro over any other brand, but it is hard to find online. $50 for a 150G bucket at my LFS and all 3 of the major levels are way up there.

Other than Tropic Marin, which I could never justify the cost, all the others for the most part need some type of boosting before you use it. Either Calcium or Magnesium is low on the majority of salts I have tried on your list. That said, if you have to test and add stuff to freshly mixed water anyway, you may as well go the cheapest route on salt, ie, something like Instant Ocean and just add your own CA/Mg.

Since I am starting a new tank, I recently asked the chief aquarist at the Cleveland zoo what they use.
They make their own to the Instant Ocean formula.

I like Ace's idea of just adding your own Ca/Mg as needed.

I use the instant ocean and have been told before that if you do regular water changes that it is fine.

Depends on your CA depletion. Instant Ocean usually has CA in the 320/340 area which is considered low for most people. If you only have softy corals this may be ok, but if your into LPS, or worse, Clams and SPS corals then Instant Ocean would not be a good choice if you didn't add Calcium to boost those numbers.

For me, if I used Instant Ocean and didn't supplement with Calcium, that original 340 CA level would drop about 40 per day. After 1 week my CA would be down to about 60 by the end of the week. It all depends on what types of corals you have in the tank.

Once i have finished setting up my tank i'll be using the tropic marine salt, but over here it's cheaper than most of the others.

Out of curiosity, what CA readings are you getting on Reef Crystals? I was getting 360-380 on the last bucket I tried. Wasn't impressed, $10 more per bucket than my normal salt and a lot less CA.