I've found that Acoustic IR's while using my Acoustic is truly where this shines for me. It helps provide a more mic'd sound rather than direct in even before EQ. My chain goes Compressor > IR > Para EQ.
I've also found that Cab IR's are useful when I don't want to carry my 4x12 cab around. I can still use my Marshall JVM410H amp for the pre-amp, and with the HX in 4CM configuration. And the Cab IR's really do sound not that bad.
In a third method, I split the signal and use both my 4x12 and an IR to the PA. I could use the Emulated out on the JVM410H for this, but I'm already connected from my board to the PA for my acoustic. Therefore I don't need to take up to channels on the mixer.
