We have used colo for about 20 years now at various companies over that time span as well has some small clients in house here ourselves with several other customers we are supporting them very happy so far no issues yet! Nothing really to dislike but would like more information from our side of things when it comes down too specifics or something not quite clear enough.
Not much I can say is bad its all good nothing realy anything i didn't enjoy just wish could maybe ask better questions before signing up instead if they don;t know how their system works than why did you signup?