Chlorine Concentration of 35%. Chlorine Concentration of 30%.
Granulated product that immediately releases chlorine. Slow dissolving tablet that slowly releases chlorine.
Perfect when you have time to take care of the spa. Perfect when you don’t have time to take of the spa.  E.g. at the cottage.
This product increases pH level. This product lowers pH level.
This product does not affect alkalinity. This product affects alkalinity.
Lithium’s efficiency depends on pH level. Bromine’s efficiency does not depend on pH level.
Produces chloramines (harmful). Does not produce chloramines.

In conclusion, both products are just as good. 
Essentially, these two products disinfect and oxidize contaminants.
It’s up to the consumer to choose which one he prefers.