Yesterday I developed 4 sheets of 8x10 in my imitation Jobo (Simmard is the brand).
The antihalation backing didn't completely clear in the fix, so I had to remove and fix in a tray, and then washed in a tray, as I couldn't figure out how to wash the film in the drum. I scratched 2 of the 4 sheets - one removing it from the drum, the other during washing.
I then went on and developed 8 sheets of 4x5 in trays (2 sets of 4) and didn't scratch one.
Lots of comments on this site laud drum developing as much less likely to cause scratches than tray developing. I like being able to turn on the lights and do some tidying, or catalogue negatives or something instead of standing in the dark carefully shuffling, but I was also looking froward to scratch free negatives all the time.
I have scratched negatives in trays, but not very often. The percentage is higher I think with 8x10 - I've only developed maybe 50-75 sheets of 8x10 and hundreds of 4x5s over the years.

Any helpful hints from the experienced? Thanks