If you live in a part of the country that has high hardness fill water you might be better off using liquid chlorine as the granular pool chlorine does contain calcium which may increase your pool water hardness.
As to which one is better; I think both kinds of swimming pool chlorine will do a great job sanitizing your pool.
For ease and convenience I always go for Calcium Hypochlorite.
I prefer cal hypo. because it's a bit safer, lighter, and easier to store than regular liquid chlorine. A drawback is that places that may have higher calcium or hard fill water shouldn't use cal hypo. because it introduces more calcium into the pool.
For sodium dichlorite triazinertrione, I think you might be referring to sodium dichloroisocyanurate.
This is a granular, stabilized, and fast dissolving form of pool chlorine and is often used as a pool shock. While Dichlor does add pool chlorine it will also increase your cyanuric acid (CYA) level while lowering your pool water pH level. Take care in using Dichlor as your CYA can get out of hand very quickly.