practical for the well versed, a great study tool

As always, Dover is great. These scores are excellent tools for the student conductor, composer, and music historian, as they are taken from the reputable Bach Gesellschaft editions. The printing is neat, clear, and fairly easy to read. As far as the varied clefs go, they are an appropiate preservation of the original. If one is well versed in composition, and I dare say a flexible and conducter too, there should not be a problem. We deal with transposing instruments, right? How hard can tenor clef be with a little practice? Anyway, they do help to differentiate between the parts with only a quick glance- better than all treble and bass clefs in my opinion.

Mixed Clefs Mixed Reviews

Having all of the these works in one place is a great resourse, however, the choral parts are written in mixed clefs (i.e. soprano, alto, tenor, etc.) making it completely impractical for rehearsal use.

Given that 5 or the 6 motets are unaccompanied, I would recommend buying individual choral scores instead.