I use to have the Placette active linestage (it had a unity gain buffer that made it active). I heard it against the passive and I liked the active version more because it sounded more dynamic.
I've also heard a light dependent resistor-based passive that was operated by remote control. It was pretty good sounding, although, it was bettered by a tube-based active in a mini shootout conducted by a friend.
The one that has me curious is the remotely controlled autoformer passive made by Dave Slagle. I like transformer-based passives, but, most have too few volume steps and are not remote controllable. Slagle's unit has many small steps, remote control and a balance control. I believe he sells his unit through a company called MyEmia. I've heard systems he put together for shows that sounded quite good, but, I haven't actually tried one in my system.