I have raised Tunis and Hair sheep!
The Tunis have awesome wool! They finish very well, but their finish weight isn't very high, maybe around the 90-100lb mark! So are a little bit smaller than some breeds! They are awesome in terms of temperment, good mothering instincts, very thrifty eaters, and lots of milk! They don't always have twins or triplets though, in terms of profit. Their meat is very mild, even the mutton has no"sheep" taste! I love the tunis as they are cheap to feed and can be bred to many different breeds!
The hair sheep in my experience, take a little longer to finish, but do finish around the 90-100lb mark as well! They are easy to get along with, but you better have good fence because I find they are escape artists, and are very agile! Lol, once they find out the pasture is greener on the other side, good luck keeping them in! They have a "no-shear policy" which is very nice. Their lambs are tough when first born, and the meat is also very mild! I find they are not quite as thrifty on the feed as the tunis and don't have the milk volume! Their appearence is much more colorful as they come in many different colors and the Tunis is just white wool and red face and legs!
Sorry, I don't know anything about Jacob Sheep!