If you need 12mm bits; the OF 1400
Otherwise; the OF 1010 is so much smaller, lighter, etc. etc.
As for possible copy ring inaccuracy with the OF-1400; how much accuracy do you need? If you need to change the rings often, the OF-1400 is a huge time saver. Same with the swiveling dust cap underneath; near zero time to install with the OF-1400, a pain with the OF-1010.
I have both. If I set my my CMS with the OF module; the 1400 goes in there to leave the 1010 available for other use. besides the CMS it's only for some 12mm bits that I use the 1400. Or when there is some repeat work where I need two different bits; then I can leave one in the 1010 and the other in the 1400.
But now that I have a MFK 700 some work of the 1010 is taken over by it.
I am in Europe. We don't do 1/4" and 1/2" bits here. It's 6mm, 8mm, 12mm. Personally I only have 8mm and 12mm. I don't want to own any other sizes because that would mean acquiring other collets too, making it nonsensical. When I looked for an edge router the MFK 700 prevailed because it took 8mm bits where some other edge routers are limited to 6mm.