Here are the basics.
Indica is THC dominate with small amounts of the other cannabinoids. Indica strains are said to be good for pain management.
Most users describe Indica as a nighttime medication and Sativa as a daytime medication.
Sativa has a broader cannabinoid profile, CBD and CBN most notably with smaller amounts of THC. However, this doesn’t necessarily mean that Sativa isn’t as strong. The other cannabinoids are said to have an entourage effect or a multiplier to the THC in any given Sativa strain.
With the advent of testing, I have noticed good Sativa tests very similar to OG strains.
Strong sativa can be the best all around high in my opinion. We all have our favorites.