@lloydc similarly to what @mulveling shared here, I did the something comparable. Started with KT88s in one amp, then KT120s, and KT150s in two different amps. The past year I stored the KT150s and tried KT120s again - - but let them burn in at least 100hrs before making judgements too fast. Very nice at 200hrs+, liking them.
Previously like many others, I kind of overlooked KT120s and jumped to KT150s prematurely. Don’t get me wrong, KT150s are nice and can do well with the right input tubes, and caps, and cables for the amp - - however, once the KT120s finally settled in they offered the balance between the two mentioned by mulveling above.
Re-discovered KT120s again lurking back over a whole bunch of old Conrad Johnson threads. Some of the CJ amp guys were diehards about 120s. I see/hear more now.
I liked the KT120s well enough recently picked up another quad just to have them as spares if that helps add confidence. The "balanced" word mentioned comes to mind for me too. They are still nice, rich, but not spiking in any area imo. And, there are some who rave about new-repro GLKT88s, had those before, they are nice too!