I know this is an older post, but thought I woudl reply. I have mixed fronts before, but after a while you wont like it. It just doesn't look or feel right. If you are asking this question then you probably already are second guessing mixing them, so you definately wont be happy doing it. As for variants; I currently have colonies of Burundi, Moba, Kapampa and Mpimbwe. I honestly like them all equally, but you get your best bang for the buck with Mpimbwe. You can get F1s for $5-$6 or nice large WC for $60 a fish. If I could do it all over again I wouldn't have gotten the Moba. They are hella expensive. I have some Mpimbwe that are absolutely amazing. I think you will be happier with 3 large WC Mpimbwe for $180ish compared to one WC Moba. $30 for 1 F1 Moba vs 5 Mpimbwe F1s. I really love Burundi, but if you look around you can get F1 Mpimbwe for the same price and they sell and look much better than Burundi.