Intermediate funds will eek out some small extra capital gains in a normally sloped yield curve, which lets say happens about 1/2 the time. They will break even if the yield curve is flat (return only their coupon yield), which lets say occurs 1/4 the time. They will do worse 1/4 the time when that portion of the yield curve inverts. So in general it seems like IT would do a little better, but total bond market funds are remarkably stable relative to their yield and duration.
Put 6 in one of them, one half dozen in the other. Actually no probably not much sense owning both.