Pygmy cories are more active. The first few weeks you have otos, they will flit constantly around your tank like, "Food food! I need food! Oh, there's some!" Stop. Nom nom nom. "Oh my god, where's the food!" More flitting. But then they get settled in and your tank starts to look like an opium den with fat, lazy otos lolling around. You will be stricken with the urge to poke them to make sure they're still alive. Don't- it means they're happy and comfortable. If you have lots of plants (which you should if you get otos), they will hang out on the leaves and you will get to spend hours of fun playing 'Find the Otos'. That being said, I love my otos, but if it's activity you want to see, stick with the corys.
I do not quarantine my otos because they are so sensitive when first brought home. The only way QT could be done safely, IMO, was if the tank has been set up and running for a while, perhaps a grow out tank for plants. They need biofilm to eat and it's critical that they have food that they recognize as food when first brought home. When I add new otos, I also add half a dose of Paraguard to the tank for the first couple days to prevent spread of parasites/bacteria.