Those are nice and clean looking, but I agree that having separate containers is nice. Every now and then I have too much time on my hands and decide to clean out my dosing containers. It's a lot easier letting one get empty and lifting it out than it is to wait for all 3 to be empty at the same time or dumping/pumping them out.
Mind you I'm not the example of attractive dosing containers at the moment. The 170 is running on Simply Orange juice containers (1.5 L) and the big tank is running on the same for the smaller dosed items (iodine, nitrate) and pairs of 5 gallon water jugs for the main consumers (Ca, Alk).