HiTresa;
I've never seen the 31MM type 5. Why? It costs about $600. Don't know anyone willing to spend that on an eyepiece. Can't comment on that. The Radians are great. Especially for eyeglass wearers. They all have 20MM eye relief and an adjustable eyeguard. I tell people they can leave their glasses on when I have it in the scope. I have the 8MM which I use on the moon and planets. It's outstanding! I use it also on very bright planetary nebulas with a ultra block filter. No problem with having to get yopur eye too close to the eyepiece. Very comfortable. You'll be happy with them. Price $228 for all sizes. Not bad.
That's it;
BOB SAL