There have been a few articles about, a particular advanced aquarist one is in there too.
http://www.advancedaquarist.com/2005/11/aafeature1
I don't think there is any one "perfect" salt. Instant Ocean seems to be the best as far as not introducing stuff you don't want, but then again it also is a bit lacking on the calcium & magnesium, but mixes to a higher than normal pH. Oceanic on the other hand is loaded with calcium, but it also has quite a large numbers on other metals, aluminum, manganese & zinc.
Personally how fast it disolves really should not matter. You should NEVER add salt directly to a tank and then water and mix in the tank (only exception to this is if the tank is
completely bare and it's the initial mixing), you really should have your water mixed up for 24 hours just because you physically can't see salt crystals doesn't mean that everything is mixed up nicely. As long as you have a decent powerhead in your mixing container then after a day most all the salt should be mixed in nicely.
Now what should YOU use? There is no perfect salt IMHO, but you should choose one based upon your setup and what you want. If you have nothing but fish or soft corals, I would probably say go with instant ocean. If you have stony corals and need higher calcium go with oceanic unless you have a calcium reactor then I'd say go with something else, instant ocean is nice but it's lacking in calcium so you'll go through your calcium reactor media quicker.
As to where to get it, I'm lucky, I have a shop that gets pretty much any kind and sell it for $10-$15 per 50g container (depending upon brand, IO is $10, something like Kent is a bit more pricy). Unfortunately this doesn't help you since you don't live here. Online you pay for shipping, and that's the trade off you have to deal with, occasionally in the pastthough places like Dr. Foster & Smith have deals that allow you to get salt without paying for shipping, but that really is not the norm for anyplace. So either buy locally or pay for shipping, no way around it really unless you wait for said deal and stock up for a long time. Another option is to talk to your LFS owner and see if he can get any sort of discount if you buy in bulk, say 1000 gallons worth, you might save a few bucks per container but then you need a place to store that much.