My dogs are Mizpah and Middlepos descendants and I am very pleased with the outcome. I do think there is an issue with some of Middlepos Simpson's offspring. There have been some heart problem on his side but no one can confirm it.
Mighty looks like good old blood and Marvell is full of great bloodlines including Dopper, Linjo, Ysterberg, Mizpah (old) piona, and many more of the old lines. i shy from Caberet but it looks like they had very few from them added to the lines. Older Mizpah dogs are great with offspring from Searsant, Blackie and Africa II. But you have to be careful of the Mizpah line as the old kennel name was purchased by Tim Dold and he does not follow the true spirit of Mizpah. The true kennel is owned by Carin York-Hart and it is now called Authentic Mizpah or just Authentic. Time also owns the Blitzkrieg boerboel kennel and they breed black dogs out of standard.
Some of Centurion Boerboels descend from Middlepos. Here is a link to the Boerboel Pedigree database. You can pick a kennel then a dog name and trace it back to it's ancestors. Watch out for breeders like Caberet, Spitsvuur, Alpinelion, PZD, Blitzkrieg < those are just the short list. If you see pics of a black dog on the right just move along to the next breeder.
http://www.boerboels.com/pedigree/pedigree.php?K_ID=2418&S_ID=45619
oh Savannah is Odi's half sister.