I've used a friend's Katana 100 series one for a while before getting Pod Go, both for practice and in rehearsal. It's a very nice sounding amp (and beastly loud if you need that) but in my opinion with quality IRs you can make PG sound better.
Also in rehearsal or gig scenario PG is much more user friendly when it comes to tweaking your sound on the spot, without hooking up a computer and running software editor. Katana's panel controls are somewhat limited. PG also offers many more ways of switching to different sounds or varieties of your basic sound. It also works better as a recording device, in my opinion. Expression pedal is also a nice option to have, not only for wah or pitch effects.
However Katana is a self contained solution, with PG you also need and an FRFR or a power amp and cab, if you want to play with people. Being a bedroom warrior and not playing in a band anymore, I'm using PC speakers with PG and sometimes I just miss having an amp with its heft and true guitar speaker, if that makes sense.
Are you more of an amp guy? Can you crank your noise making device up a little bit? Can you live with 3-4 basic sounds? If so, I would stick to the Katana. Do you want to mostly record, need many tone sculpting options and tweakability? Then go for the Pod.
If you can afford that, try combining both :)