I have both Brands of dies and like them both.
You asked about neck bushing dies, BUT:
One advantage to a Forster die is that you can order a non-bushing full length sizer die with the Neck ID custom ground to whatever dimension you prefer. Costs about $15. I've found this very convenient for a .223 Rem die I ordered from Forstner. I had the neck ID ground so that it barely sized the neck any smaller than necessary to hold my .224 bullets. I leave the expander ball in the die and it comes back through the neck with very little expansion. Maybe none. I don't outside neck turn my .223 casings, so this allows me a lot of flexibility in using this die on a variety of Brands of casings.
My measured runout was greatly reduced compared to the former RCBS full length sizer die I had been using previously. The RCBS die was way oversizing the necks, and then pulling the expander ball back thru the necks of the casings was causing a lot of casing neck runout.