The experimental active moving step up preamp is much more dynamic, with better imaging, better resolution. It's also huge, would be very expensive and most important of all it is too noisy to become a commercial product. Everyone would complain. I can listen to it and enjoy it, but I very clearly understand its limitations.
Aaron brought a very interesting solid state step up preamp made by Pioneer in the late 70's as a statement piece. I guess it was something for the home market. It was very impressive, dead quiet and pretty close to the tube one sonically. It had a bit better bass and I felt the tube step up had a bit more musicality in the midrange, possibly due to having less feedback. They each had their advantage over the other. Neither one is actually in production these days, so the session was more of a DIY experimenter playtime than a new product demo.
If you want something to play with, you might look for a Levinson JC-1 (battery version). I had one many years ago that was quite nice. I think they go for around $300-400 used these days. I'm sure I paid less than that, probably swapped something for it. There was also an AC powered one made in the late 80s by Klyne Audio. I think it was called the SK-2. I had one on loan for a while and it was nice too. I imagine they go for a little more than a JC-1. I would guess that both of those are 2SK120 fet based preamps.
