Like many of you, I have used both plastic and SS for both 35mm and 120. I am using a Unicolor drum now and have been for some time. Although the reels are plastic, I've been told they are teflon coated (I can't verify this) and they very easy to load. One trick that I've found helpful with Unicolor and Paterson reels is snipping a small bevel at the end of the film that goes into the reel. It seems to eliminate the film edge catching on the reel. With 35mm, be sure to not leave a hook from a sprocket hole.
I've used both stainless and Patterson and I prefer Patterson. There are two BIG tips in using them. First, because you're essentially pushing the film through the reel, Patterson reels have to be bone dry before you can even think of using them. I let mine dry in a dehumidified basement for 24hrs and it seems to do the trick. Second, clip the corners off the leading edge of the film that you insert into the reel. It *really* helps the film not snag as it's pushed onto the reel. I use a 3 reel tank and I can get it loaded in a changing bag in about 10min. No dimples, no ")" marks, no film touching each other or jumped channels and very little frustration.
I developed 4 rolls of 120 on SS reels this morning - two double SS tanks (each tank holds two 120 reels and a 35mm reel). The loading went without a hitch -- don't know the brands of the reels -- a mixed collection. The reels and tanks were a little damp (someone used them the night before), so I dried them quickly with a hair drier. I started one tank developing 2 minutes before the other.
I do mosly LF, but learned photography with 120, and have always found that 120 reels load easier for the beginner than 35mm (both formats using SS reels). I have gotten good with 35mm on SS reels (all brands, but Hewes kick ass) after helping students for the last 20 years. We have plastic reels and tanks, but I have never used them. We have had to replace the plastic lids for the SS tanks, but the takns themselves are too strong to damage. We have boxes of them -- much more than we can use! The SS reels don't like being dropped, though.
We (the university) got a little extra money at the end of last year, so we bought 24 Hewes 35mm reels -- I see far less bad rolls of film from the students this year.
At least with LF landscape, a bad day of photography can still be a good day of exercise.