i just brought home my tribute 140c. (rebadged 855). and i do love it. i am a long time viking owner--will not give up my 350 for anything. from what i understand, the newer ones have worked out the kinks that the older ones had. having said that, they are now assembled in china versus sweden. my dh did some investigating. the parts are designed and machined and sweden and shipped to china for assembly. kind of like piaggio scooters. parts made in italy, shipped to china for assembly.
the biggest difference between the 140c (aka 855) and 875 is that the 140c has less stitches, no automatic thread cutter and has a manual tension set. the 875 has more stitches, automatic thread cutter and an electronic tension set.
i would suggest you sit down with both and try them out. bring fabric YOU will be sewing on.