I think that the only brand on the market older than Hugy was the Franke and Heidecke Rolleimarin... or maybe Ike predates the latter.
A few years ago in the Caribbean, the captain of a liveaboard was using a borrowed Hugy for the N90s/F90x. He told me that it was the best housing he ever used with this camera.
I never worked with one personnally but looking at the satisfaction level of Hugy fans I understand that it is a great product.
My personal note regarding the Hugys has always been the shutter release and handles... or absence of the latter on the right side of the unit.
Being a long time Aquatica user, I tend to favour straight handles and shutter release levers that are akin to what I am used to.
Alex is right, Hugy is way more popular in EC, has to do with distributorship I guess.
Michel