Previously had Katana 100W Mk2, I always used the Power Amp In input with my Helix LT. If you want to use cab simulation, forget about Katana since Katana's power amp colors the tone.
Fender Tone Master blows it out of the water. Really good FRFR speaker, volume-wise it's able to keep up with my rock drummer and bassist at 50% volume.
It's really simple to use, has one input and one output (for sending the signal to FOH). Also, it has a simple EQ (bass, mid, treble) and a cut knob. Highly recommend it!