I thought you were including 'Vs' - that would have been my choice.
Had Hope Mono M4s and now using Magura Marta SL Magnesiums. Similar performance but the Martas remind me of my 1980s teenage bedroom with their black white and red colour scheme... which I like.
I voted SLX. After eight years of using various Hopes on my bikes, I finally gave up in 2008, bought some XTs and was a happy chappy. SLXs are a similar design, a bit cheaper and absolutely awesome for the money. Simple, fuss free effective braking with ample power.
Don't get the fuss about hope. I know people want to like them cos they're british and all but for me they're way overpriced for the way the perform. They look pretty if that's your thing, but performance is mine and i've always found hope brakes really ordinary.
Slx are awesome brakes, I prefer them to the XT version as the bite point on thee slx is consistent, unlike the xt.
Hope looks nice and im all for keeping it british, but everyone I know who had hope has had problems with them, mainly stuck pistons, but nobody I know who uses shimano had ever had a problem with them