I got a Katana 100W and it is under the bench now. I am using the Eleven with a Tech 21 Power Engine 60 and FCB 1010 with Eureka FW. I've got the FX loop going to a Behringer audio interface connected to iPad running Quantilooper.
I am not sure about the sounds because the Katana makes some nice sounds and so does the Eleven. I'm using the Eleven because of the bigger/better UI and more flexible MIDI controllability.
There are definitely some limitations on the Eleven in the FX zone, e.g. no auto wah or pitch shifter/harmonizers. But I don't use those much anyway and I have a Line6 M9 if I really just had to.
I also have my bass and GK 200MB on one channel of Quantilooper.