Hi,
As far as I know, it's considered to be a top-five MA program. I talked to some scholars and students about this because I was also accepted for the MA and had the same question. It's an unusual program because it's only one year and you spend that year abroad, but from what I hear, its reputation is awesome, and anyone in academia or in the language field knows about it. I think it's confusing to find information on this because Middlebury is an undergrad-only college so it's not at the forefront of rankings and reputations anyway. That they only offer an MA in languages adds to the confusion. It's a really specialized program.
good luck!