Pros: Smaller, older, more reasonable userbase means participation is (for me at least) less intimidating and more meaningful. The atmosphere is very different and more pleasant. People are generally polite here. Comment fields have more interesting replies and less one-word comments and shit posts and memes and whatnot.
Cons: less content, not really feasible to endlessly scroll as an infinite distraction faucet. The userbase has clearly defined interests and certain fields such as sports don't have particularly good representation here, compared to tech fields for example. Comment fields are emptier.