I ride on both B-17 and B-68, not at the same time however.
The B-17 is on a CrossCheck with Albatross handlebars that are level or slightly above the stem, so I sit fairly upright.- it is pretty comfortable.
The B-68 has been on several bikes. The above CrossCheck. A Trek MTN bike converted to commuting with handle bars slightly above the stem. Also on a Schwinn tandem as a pilot with the geometry similar to a comfort bike, handlebars above seat.
B-17 was better on the CrossCheck. B-68 better on the MTN bike, my teenage son grew into this bike and now claims it for his own. He has ridden it a couple thousand km, tried other seats, wants to stay with the B-68. The B-17 has a smooth surface, which I personally like better than the slightly pebbled surface of the B-68. Hard to tell which is more effective, until you actually try both. While I have slight preferences, either have been pretty comfortable on any of the bikes I've tried them on.