Dunno about other people, but I personally don't like the new horse battle helmets when they have non-color-matched horns. If you swap the horns from the prison and castle set, they look a lot better...pearl gold horn to metallica gold helmet and pearl light gray horn to metallic silver helmet...it makes it look like one solid piece of armor. Since they're both the most expensive sets, most people aren't going to have an imbalance (of the silver and gold helmets).
The only problem is that there isn't a color-matched horn for the pearl dark gray battle helmet in the much cheaper prison cart set. So I'd think it'd be nice if in a future moderately low priced set, they release a horse with a metallic gold helmet and pearl dark gray horn, so the parts can be swapped with the prison cart set. Or just toss a handful of extra pearl dark gray horns in a set