Language immersion programs -- Fairfax county

Anyone have any info/insight on the language immersion programs offered at some of the fairfax county schools?  There is one school by us (Rose Hill; not in our district, but not far) that has a two-way immersion kindergarten program and then partial immersion for grades 1 through 6.  It sounds very cool, but I don't know anyone with older kids that have gone through it.  Just curious if anyone on here knows anything about it or has heard anything about it.   We wouldn't be looking to enroll our son for another year, so I do have time to find out more info and go to their orientation meetings, but it's always nice to hear what other people have to say:)