Like the other reviews I had my doubts about Behringer devices. My band has started using 2 keyboards and 4 acoustic guitars and we had plenty of grounding issues and extra noise in the PA. instead of buying a bunch of passive DI boxes I decided to try this one.
I immediately plugged everything in and turned on the PA. ABSOLUTELY NO NOISE IN THE PA! Plenty of headroom and no feedback.
The only downside (maybe the reason it works so well) is that it has to be powered. So now I have a small case that I have to find room for on stage.
Other than that the Ultra DI Pro is worth it's weight in gold.