I have. Separately and together. Both have a clean, objective, bursty sound. Not the most tone-density you can possibly get but transparent, revealing, fast, agile. Medium power triode p-p amp using 6as7. It sounds more objective than most triode amplifiers; less romantic but still toneful and musical. Excellent power supply. Not the quietest amps you can buy (sn -84dbm). Well built, great auto operation. Seriously engineered. As a linestage the Conductor is less distinctive sonically than alternatives, IMO, but it does nothing to detract from the good qualities of the Baldur. What does distinguish the Conductor is it is capable of being very energetic. It has a power supply bigger than many amps.
I've never had personal time with the combination, so these are impressions. I did hear Baldur 300 in my own systems several years ago and what I've heard in alien setups was not contradictory. You have to need or want that level of triode power. If you have sufficient speaker efficiency to do with less, I like simpler. While the Baldur certainly minimizes what I'm about to point out, some of the slight haze you hear in massed-output-tube amps creeps in.
Phil