The powdered and puck forms of chlorine are more concentrated per WEIGHT so you have less to carry, but they are far more expensive per pound such that they are not all less expensive and as was pointed out some are quite a lot more expensive.

The main problem with the other forms of chlorine is what else they add to the water. The following are chemical rules of fact that are independent of product concentration or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.