Apparently I’m an oddball who loves pellets in the trailer. Obviously I wet them. I stand the bags up in my manure cart, cut the tops, and wet them in the bag. By the time I wheel them to the trailer, they’re broken down and expanded most of the way, and what hasn’t broken down yet does so quickly once spread. Yes it gets in the seams between mats, but so do shavings. Pellets absorb moisture from manure quickly so on long trips manure remains balled up and pickabe, rather than packed down in to a heavy heap; may not be important for all, but I like the composition of manure that I have to pick from pellets rather than shavings 
I haven’t ever had the dusty problems with them that others complain about. I think shavings are far dustier. Never had an issue with slipping on properly wetted pellets, even after they dry in to sawdust.
I seem to be in the minority. I love pellets (expanded and dry) for my trailer. I do have rumber flooring, so no mats to shift or cracks for bedding to get stuck in. I find that they aren’t any dustier than flakes, and don’t blow around. they absorb urine wonderfully and keep the floor from getting slick. I am careful to sweep the springs of the ramp. I trailer out 2-3 times a week and find that I average a bag a year in a 2H. In the beginning most of the bedding lives under the mangers and I pull it back as needed.
I sold my 2001 trailer in 2022. I always used shavings when I hauled. I cleaned wet spots and manure after every ride. Dry bedding was flipped towards the middle of the trailer but not removed every time. I would only remove mats and deep clean once a year. I personally feel that mats with no bedding is slick. My wood floor was fine. I am still in touch with the newer owner. Trailer is 24 years old and floor is great. No rust on side walls. Many dealers are not horse owners.
Trailer was never garage kept, only kept on gravel pad maybe 50% of it’s life.
Current trailer is 2008. All 3 owners have used shavings for hauling, Wood flooring and side walls are in great shape.
I like the mini flake shavings the best for the trailer but have used pellets in a pinch since I have them on hand to use in stalls. The way I do it is lay the bag of pellets down in the trailer, cut a big X in the bag and pour in a small bucket of water. The pellets absorb the water and fluff up after a few minutes and can be spread around easily.
