As you have asked for System 54 originally, go and play one. I am not a bari expert at all. My only experience was a short test drive in a music store when I didn't own a bari myself. The specific instrument was very sweet and lush. Response was really great over the whole range and intonation seemed good (no tuner at hand). Pinkies were a bit of a stretch. Caveat, I have never blown a Yanagisawa or a Yamaha baritone. Nevertheless I believe the System 54 would be worth consideration if you have a chance to test them.
Alphorn