Depends on the scale you are feeding - bins are great as they are easy to move around etc, bins are great if you feed several horses. I prefer metal over plastic - mice rats etc can't chew through metal.
I have always used dustbins, but after a few years they have all got chewed up quite a bit. I actually fell in to a metal feed bin once trying to get to the last bit at the bottom.
I have a wheely bin,like you get outside your house if you know what i mean,it was a bit more expensive but its easier to move with the wheels with food in and i have a weak back so got it for that reason,it holds a good amount too,really recommend them
Wheelie bin for Hi FI (you can just fit a new bag in if you squish it down). Plastic bins for rest, easy to clean and move. Never had a problem with rats/mice chewing through them.
Black dustbins for me - lasted me years - easy to wash out, have never had a problem with mice/rats and easy for me to move around the feed room if I need to. Cheap as well - what more could you ask for!