Dutchmen and Keystone are "cousins" to each other. Both are ThorIndustries products and are pretty much similar in every way. They are both manufactured in Elkhart, Indiana and their manufacturing plants are just a short distance from each other.
We took a tour through the Dutchmen facility several years ago. In all respects, they are pretty much identical in build, quality, appliances, parts, everything.
We've owned both a Dutchmen (new) TT and a Keystone Springdale (new) TT. Both were good campers. Our needs changed and that was the reason we ended up trading for something different. We are on our 2nd Keystone now, Outback. It's been a good camper also.
When I look back, I feel the Dutchmen was a bit more solid, but it was also only 18 feet long. Maybe the size just felt more solid. The Springdale was 31 feet long. Maybe because it was bigger it just felt different. Funny though, both campers weighed about the same, but they were a few years apart in manufacturing.
It really is a flip of the coin. Floor plans are almost identical too. Don't know if you have done so or not, but if you can actually go see both models in person, it may give you a different feel one-over-the-other. The color of the wall paper, the design of the cabinets, the size of the refrigerator, the color of the floor, one may be more pleasing than the other.
And then there is the price? I'd consider the cheaper one first, even if was 50 cents, it could just enough to break the tie. They both have an outside kitchen. Look at both of them and see which one works better for you.
Good luck!
