My last mare had RAO so I used haylage. My supplier did bales that were about 80% of full size which was perfect for me with 2 horses. However now I just have one TB and a shetland so I'm moved onto hay. And actually the TB seems to eat more of the hay. It's also better for my shetland. The problem is, I don't have storage - just a large corner stable that is used as my hay, feed and tack room. I have just managed to squeeze 4 round bales of hay in to it, so I've also bought 4 haylage bales that can sit outside until the weather gets colder. I'll use the haylage when it's really frosty as it will last longer in cold weather.
Bit long sorry - but essentially I'd prefer to just use hay but storage is an issue hence the mix.
We have some horses on hay and some on haylage - just depends on the horse individually and what suits them best. We look at weight and work load mainly - I prefer to have the horses in heavy work on haylage if they suit it. We're lucky the hay we have is good quality so we haven't needed to move any onto haylage for this reason or soak - which is my least favourite job in winter!