I took a look at their Website and have to concur with you that they are "Brokers" which tells me, in my cynical view of the world, that they simply list (and have no interest other than profit) Buses for sale.
Did I mention that when it comes to spending MY money...I'm terribly cynical and suspect?
I have no Pro or Con opinion of this Company and have never had dealings with them.
I can only offer the standard caution in dealing with anyone who deals wholesale in used equipment, "Caveat Emptor" (let the buyer beware).
A broker is only listing items for sale and may not know anything personally about the item being offered. It may have been run hard and put up wet (as we who know horses say) and might spins yarns about who owned and/or traveled in the bus...but in the final reality that doesn't make a tinkers' darn about the mechanical condition.
I wish you well in your quest for the perfect bus...may the Bus Gods smile upon you.