Ive owned both and agree that its hard to beat a large male doviis argression. However, umbee are very agressive too. Both species are especially while spawning. Both fish are going to be a toss up as far as which fish will be more agressive honestly. Both fish are also very intelligent too. I don't think you can go wrong with either fish if you're looking for a large smart agressive cichlid. However, regardless of how large a 250 gallon aquarium may be a male dovii can cap out at 24"+ and at that size is still a very very active swimmer. While it's not as common for umbee to get that large, they can. However, they are a little more lethargic when large. For a 250 for life I would go for an umbee pair.... but that's just me =]