Since the question is about 120 reels, I'll recommend steel reels. I'm a recent convert from plastic (Patterson) to steel reels. I moved to steel reels after I ruined two rolls of film trying to load it on plastic reels. It took about 30 minutes to load it on the reel and finally the film was all kinked. The plastic reels have to be really dry. If you're using a darkroom bag to load the film, your hands are going to sweat after a couple of minutes. This will make the film stick to the reel and it'll refuse to load. 35mm is easy with the plastic reels because it is more rigid and not as wide as the 120.

Anyway I tried the steel 120 reels and everytime I was able to load the film in less than a minute. I sold all my plastic tanks (had 6 patterson) and bought some kindermann tanks and reels. For 35mm I bought the Hewes stainless steel reels and it's a pleasure to use.