I may be able to provide some insight to this topic. We have cattle, chickens, pigs, turkey, quail, ducks, and rabbits. We have also had sheep, goats, pheasant, and a horse. The trick is to have a variety of livestock that can provide different things throughtout the year. And if one animal fails, or gets eaten by predators, then you have the others to fall back on.
Cattle eat alot. They graze almost non-stop, so using rotational grazing methods is a must (unless you have a few thousand acres or own the feed store Lol). They are difficult to butcher on your own, but provide a whole lot of meat all at once, whereas something like poultry or rabbits are easy to process as needed (no deep freeze required). Turkeys are a nice trade off for size and grazing needed, but you have to get some that are nice or you will spend alot of time running from them! Ours are so sweet but our friends have turkeys that run you down.
For me, I'd say rabbits and chickens are the best because their meat is lean, rabbit droppings can be used right away in the garden, chickens can help till the garden and add nutrients, both are easy to process as needed, and they both can graze so you wont need large amounts of feed or grass all at once. Just my 2 cents. Im sure there's more, but it's still early and I havent had my hot tea yet....(btw, the mini-horse was a bad idea for us. Beautiful little guy went down to the pond for a drink and a gator got him. So environment is definitely a consideration when choosing animals).