I have Forster, Redding and Whidden mic seaters from all of the above. My only Whidden dies are for my Creedmoor. Quality is very good; at least as good as the others, maybe a bit better but as all are very high quality I'm not sure how much difference it makes. It seems a little more sensitive than the others and I believe he tries to make a single adjustment on the micrometer close to 1/1000 of an inch of seating depth.
I typically buy based on price for the three companies above. Forster seems to always be the lowest and Redding and Whidden about the same. As Forster doesn't make a Creedmoor setup why not give them a try? In either case, you won't be disappointed.