This is my 2nd tractor with Rim Guard. The first was my 1886 with a FEL on it.
It originally had unloaded turf tires on it and actually got 'stuck' on a flat yard. It was really wet, and with no weight, the rear was too light to get any traction. It just sat on top of the grass and spun.
I replaced the turfs with some CST Ancla tires filled with Rim Guard, and it walked out of where it was 'stuck' like it was on dry pavement.
If you need/want extra weight on a tractor filling the tires is the best option. With the weight in the tires, the axle/frame isn't carrying the weight, like with a weight box or other hanging weight. It lowers the center of gravity which helps on slopes. It's much more cost effective than iron wheel weights.
Rim Guard's advantage is that it much heavier than any other water based fluid (11lb/gal vs. 8lb/gal) with the possible exception of Calcium Chloride, which has some serious drawbacks, like being toxic to animals, highly corrosive and environmentally unfriendly. Spill CaCl2, and it kills vegetation, and will kill animals that might drink it. Rim Guard, being basically beet juice, is non-corrosive, biodegradable, and is actually approved as animal food.
Oh, and it is good to -35F.
About the only negatives is that it's not available everywhere, and you do need to make sure that you have metal valve stems as opposed to rubber ones.