Is it a good idea to cook stew in the oven in a stainless steel pot?
Conventional wisdom says use the dutch oven. Why? Because dutch ovens are heavy and have a lot of thermal mass. Higher thermal mass tends to even out the temperature experienced by the food inside of the cooking vessel. All ovens oscillate above and below the set temperature. That means an oven set to 250 may oscillate between 225 and 275 to maintain an average of 250.

That said, when cooking wet foods in the oven the quality of the cooking vessel really doesn't seem to matter. A less conductive material may take longer to cook the food, but from a scorching or food quality standpoint I think you will find there is no appreciable difference.

If we were talking cooking bread in a pre-heated dutch oven vs a pre-heated flimsy steel pot, there would be a big difference.