This is a bit random, isnt it? Baileys No 4 is excellent for keeping weight on the Moose over the winter...but I wouldnt have fed it to my last loan pony. He was on mollichaff when he came and was like a small rocket as a result, but on the other hand, my current loan horse is on mollichaff as well, and doing beautifully on it, no nuttiness at all !
They are all major companies and to be honest I wouldn't say one company was better that the other. I would be happy to feed my horses any of those brands.
There are of course many other good feed companies not listed on your poll.
I don't go by brand - I choose the right food to match a horse's individual requirements, regardless of manufacturer.
At the moment I feed Baileys, plus some straights. In the past have also used Spiller's, Dengie and Dodson & Horrell, all with satisfactory results for the horses concerned.
Ditto ali_m I love Allen and Page feeds, and they have just been given the Royal seal of approval.
However, having said this it depends on the horse and its workload and requirements each one is unique in what they need. I also use Dengie and Spillers.
I prefer to make up my own using basic feeds and a good horse balancer. I personally don't like all the weird additions to processed feeds such as wheat and soy products.