The '05-'06 ford is going to have the 6.0 in it and that's not nearly as good a motor as the 7.3. Performance-wise it's supposed to run better than the 7.3. The big problem with the 6.0 is head gasket failure. I have heard Ford did an upgrade that is supposed to solve this problem but I think I would stay away from the 6.0 although I have a friend that has had the Ford with the 6.0 and never had a problem with it. With the Dodge you have to worry about a lift pump failure that will take the injection pump out, a repair that runs upwards of 2k. You can put a fuel pressure gauge or a low pressure warning light on the Dodge. This will let you know when the lift pump fails and can save you the expense of replacing the injector pump. I hate to say it because I'm a Ford guy but if I was shopping for a '05-'06 diesel truck I would go with the Dodge.