I have a pair of FR-12s, newer ones without the hiss issue. Of all of the monitoring options I have tried through the years, these are my absolute favorite. I’ve done QSC K10s, Line 6 Powercabs, straight into various guitar cabs, straight into the PA, and studio monitors.
My band did a gig at a private party on a small lake last weekend, and I brought just one FR-12 for monitoring myself, with another line into the PA. I had the output on my Axe-FX around noon or so, and the output on the FR-12 at around 10:00 and I had enough juice to overpower the stage volume if I maxed out the volume on the expression pedal, it generally stayed at around 60% or so. Just great little amps for the application.