For 120, the AP (arista, Sagamon, etc) "compact" reels have a wide "table" at the entrance to help guide the film. This is not on the "classic" reels. Both work with the Paterson tanks. As others have mentioned the 120 film is so thin that it can be hard to feed stright.
The Jobo 1500 reels are a bit less likly to stick than the paptersons, and because of the design you can guide the film with your fingers using the Deperssion in the side of the reel. They need the JOBO 1500 series tanks. Both have been out of production, but should be back in stores soon. They are more expensive.
Stainless is great to load if you hold your mouth just right. The world of Photography is equally divided between those who swear by them and those that swear at them. If you have the knack they will work wet or dry and load much quicker than any of the plastc reels.
Myself I used the JOBO for 35mm and the Compact AP reels in an old style paterson Tank for 120 as my first choice.