I've been messing around with this setup for about 2 weeks now - not using any fx loops. I'm plugging guitar into Pod Go, & patching Pod Go L & R outs into HR FX L & R ins, & taking HR FX L & R out directly to pa.
I'm using the Pod Go for amp sims/cabs/EQ/noise gate/overdrives/wah & volume pedal, & using the HX FX for post amp modulation/delay/reverb. I also have an expression pedal plugged in to the HX FX for pitch shift.
I've created a few patches for each - eg: on the PG i have a Trainwreck patch, which consists of the Trainwreck amp, cab, eq, noise gate, 3 diff flavors of od/dist, & vol/wah. I've created other patches similar using diff amps, eg Matchless, Dr Z, Fender Twin, etc... On HX FX, I've created a few patches with various combinations of 1 modulation, 2 reverbs & 3 delays, mapped to switches, as well as always on reverb & pitch shift, controlled by expression pedal.
I've got to say, I'm getting some awesome sounds, & through my pa it sounds pretty spectacular, especially the stereo delays. I still have both units' fx loops available, I plan on putting my EHX B9 pedal in the Pod Go FX loop. When both units are in stomp mode, I have the equivalence of a pretty giant pedal board, with the ability to turn 10+ fx on/off, as well as wah, pitch & volume pedals. That's how I would use it, in stomp mode, as opposed to preset/snapshot mode.
Having said all that, I'm not sure I need all this for my gigs, which are split between Grateful Dead cover band and Praise & Worship gigs. I think the Pod Go by itself is probably all I need for either, if going direct to pa. If I want to lug my amp, a Blackstar Club 40, I can use my HX FX in 4CM.
So in conclusion, for my gigging needs it's probably overkill, but for plugging in to my pa in my basement, kicking back with an adult beverage & turning it UP, either solo or jamming with friends, it has been a LOT of fun :)