I have replaced a bunch of my pedals with this unit. Like a lot guitarists these days I would rather have a small board when I am moving around a lot. This pedal can cover almost any sound and pedal function except for a decent overdrive sound. So I currently use only 2 overdrive pedals, the H9 and a delay pedal. I can get almost any sound I need. All of the algorithms sound exceptional and are highly tweakable with the app.
My initial gripe with this pedal is that you could only use one effect at a time. I like to use chorus delay and reverb together sometimes and thankfully the H9 has a ModEchoVerb patch that can do all three of these effects together at the same time. So I'm very happy with how it sounds. I have an extra delay pedal on my board for when I want to add delay to a tremolo or Leslie sound.
I'm a big fan of octave sounds, while this unit can't get to the same level as the Pog2, It can get quiet close. It can also do the Boss Oc2 sound pretty convincingly. I have been through quite a few autowah/envelope filter pedals too in my time, the H9 can emulate a lot of the popular Autowah sounds and do a few of its own original sounds too.
I use an external foot switch to bank up and down. It makes life easier and I don't have to bend over to change patches, I would see this as a necessary purchase if you are using it live.