pokemon revolution is alot newer than pokemmo, the gym battles are a bit more challenging than the original version. it's annoying to grind pokemon with good ivs for competitive pvp especially rare ones with low spawn rates.

you can start with pikachu to fight ash in the viridian forest and obtain his hat from the mankey quest in route 9 (this part is after beating the vermillion gym)

pokemmo might be more popular these days but it doesn't have johto region unlike revolution.

revolution doesn't have breeding but pokemmo takes a while to reach the breeding stage.