That's what I added to my setup time when I decided that the onboard mic input in the psr3k wasn't giving me all I needed anymore.
I tried ... I REEEEALLY tried to love the simplicity of it, but the headroom factor is just too much of a sacrifice.
Here are my thoughts:

1) The mic input is too sensitive and there is not enough headroom for a good, solid, clean sound when you sing as strong as I do.

2) The compressor helps "a little" to smooth out the sounds, but even so - it's not a very good compressor.

3) The harmonies suffer if you use the dedicated effect on the mic channel. Seems thay vie for attention from the memory section, and the harmonizer usually looses that battle. The harmonizer works better if you keep the effect off ....... but then I don't like the effects on the lead mic anymore. Catch 22? Maybe.

4)The inability to trigger harmonies from the right hand while using the arranger in the left is bad for me. I switch betwen live and accpt bass alot, so I need the harmonies to attach to the right hand. I can also play better chord voicings with my right hand. I play some passing tones, and tension notes that work GREAT on the harmonies, but would create a weird feeling if the arranger got wind of these changes.

5) Lastly ..... the on/off is NOT instantanious in the built in harmonizer. I need to cut in and out with "split second" acuracy to capture that "vocal group" sound, like the 4 Freshman, Letterman, and Beach Boys do. That's important to my trademark sound. The Yamaha interrupts the signal for a second when you switch the harmonies on or off. VERY, very cumbersome - and I just can no longer take it.

So: Conclusions......

1) I wired the Digitech VR back into the setup and it's working great. I use a rack mount Toa mixer that has individual, direct outs on each channel, so I feed the mic into the Digitech, then I take the direct out and pump that into the Yammy mic input at a low volume ... just to get the delay effect added to the Reverb in the Digi.

2) Adding tha rack bag made it possible to stow the A/C adapters for my laptop and kb inside. The look is neat and clean, and super simple to hook up. Every wire is measured to the correct distance and held securely with cable ties. It's impossible to hook it up wrong - even in the dark.

3) End result - I sound better. I'm happier performing. The Bose has a punchier, stronger signal coming into it, and it sounds great. I LOVE it .... .and all it added to my setup time was about 5 minutes. Quite possibly less. Life is good !