Some notes on these from a Florida standpoint:
C. macrophylla -- perhaps the most vigorous of all. Amazingly fast growth. Very heavy production of big, dilute-flavored fruit. Good under lemons and limes; too dilute-tasting for most oranges or grapefruit. Very cold-tender. Susceptible to tristeza. Perhaps the most resistant of all to phytophthora. susceptible to citrus blight. It was used some in far south Florida for a number of years, but tristeza has pretty much stopped that.
C. volckameriana -- note that it's volkameriana. volck (with a c) is the spray oil. Like macro, this one is also very vigorous and heavy-producing. Became popular in Florida as a substitute for rough lemon, when rough lemon lost popularity due to its susceptibility to citrus blight. Unfortunately, volk turned out to be rather blight-susceptible too. Tolerant of all the common viruses, and similar to rough lemon for phytophthora (meaning, it's susceptible)
Rangpur x Troyer We grew this for many years and often tried it as a rootstock. We never liked it. The trees are somewhat dwarfed (its claim to fame), but are often unthrifty and poor-growing. Susceptible to tristeza, exocortis, and xyloporosis (surely a record). Pretty tree in its own right, with brilliant orange, small fruit that look like elongated Minneolas. Very pretty.
Sun Chu Sha Mand. -- excellent mandarin-type rootstock. resistant to nearly everything; reasonably cold-hardy; scion makes high-quality fruit. Like Cleo in that fruit of the scion may be smaller and a bit later-maturing than on other roostocks.
Smooth Flat Seville -- pretty much similar to common sour orange -- big, productive trees of very high-quality fruit on the scion. Cold hardy like sour. Sometimes planted with the concept that it's less tristeza-susceptible than sour, but I'm not sure I believe that. It can decline from tristeza.
