Can't comment on the Redding, but recently got a new set of Forster dies in 6BR.
The bump/bushing die works well. The depriming pin was correctly sized for the 6BR Lapua cases. If you set the die to let the shell holder contact the bottom of the die, you will bump the shoulder in the order of 0.005". Did not measure it accurately, but it was more than I wanted. I set my die so the press ram came short and only bumped the shoulder on my once fired at various loads 0.001" max. I believe this die does not form the body, so you can use the die with the top works removed as a gauge to measure the shoulder bump dimension. The die does not come with an expander ball, but you can buy it as an option. I only planned to use it on the uprimed brass (as they are reported correctly to come tight), but now am considering using it when sizing fired cases. I noticed a very tiny hole drilled off center in the side of the threaded part of the die. There was no mention of it in the instructions, and thought it was a defect. Then by chance when reading the instructions for the standard sizing die, I gather it is to help locate the sizing ball in the correct position to minimize any effect on concentricity. Will have to investigate that further. I just winged the ball position, and may have gotten it wrong. The die sizes fired cases in 6BR from about .270 to .268 using a .267 bushing with two finger pressure (Classic Cast press), and only graphite for lube. I do put extra pressure to be sure the shoulder bumps.
The Ultra Seating die with micrometer scale works well. To get the bad out of the way, the micrometer scale and numbers are kind of grey instead of white and are hard to read in lower light. They also put the zero in the range of travel. I set up for my most common bullet to read zero at the lands. Seemed like a good idea. However, when you go away from zero in one direction the scale is really backwards. I think the die would be more useful with the zero at the bottom, and all loads would be measured at some positive number. But, that may be just the way I set it up. The scale is very repeatable. I've never seen the seating rings on the bullets, using 4 different kinds of Berger. The pressure to seat seems so light compared to my hunting loads, and most of it is the spring loaded bullet guide. I don't measure concentricity, so I can report on that.
The only advantage I can think of with the Redding is that I believe they offer premium bushings -- nitrided boride or something like that. However, I have read threads that say if you grind a bevel on the Redding bushings, then they fit the Forster die.
Hope that helps some. Any questions on issues I forgot to cover, just ask.