How each one cooks
A slow cooker heats a stoneware pot from the base it sits in, with the lid on the whole time. Crock-Pot says its slow cookers reach the simmer point, about 209°F, on both Low and High; High just gets there sooner. Very little liquid evaporates, which is why a slow-cooker stew stays thin unless you thicken it.
A Dutch oven sits on the stove or in the oven, so you set the heat. You can brown the meat and onions in it first, then cover it and cook it slowly over low heat or in the oven, Le Creuset says, and take the lid off at the end to thicken the sauce.
What each one is good at
Use the slow cooker when nobody will be home: Crock-Pot says its cookers are safe on the counter for long periods, and a lower setting holds food warm. It's at its best with chili, pulled pork, soups and stews you leave for the day.
Use the Dutch oven when browning and a rich, reduced sauce matter, and when you want dinner in a few hours rather than eight. It also bakes bread, fries, boils pasta and roasts a chicken, none of which a slow cooker does well.
Moving a recipe from one to the other
Going from the stove to a slow cooker, use less liquid, because almost none boils away, Crock-Pot says. Fill the pot half to three-quarters full and keep the lid on: each lift lets out heat and adds cooking time. Brown the meat in a pan first if you want the color.
Going the other way, a Dutch oven needs more liquid than a slow cooker recipe gives, and it cooks faster. Keep the lid on, check the level now and then, and expect a few hours instead of a full day.
How these comparisons are made
Questions about this choice
Can I use a Dutch oven as a slow cooker?
Yes, covered over low heat or in a low oven, though you'll need to stay nearby and it cooks faster than a slow cooker. Crock-Pot's cookers sit at about 209°F on either setting.
Do I need to brown meat for a slow cooker?
No, but browning gives color and flavor a slow cooker can't. Brown it in a skillet first, or use a Dutch oven and do it all in one pot.