I've planted it. So far, it is has not been invasive in any sense of the word in my location (xeric California Oak woodland). No sprouts, no spreading seed, ect. Mine has been in the ground for 2 years now and it's not yet bearing fruit. It's sort of just trudging along, and not really growing that robustly, so I really can't say if nitrogen fixation has been any benefit to it yet.
I'd recommend planting it. You might also look into other nitrogen-fixing bushes like Gojii Berry (Wolfberry) and Seaberry
http://www.burntridgenursery.com/fruitingPlants/index_product.asp?dept=43&parent=28. I've got some seaberry seedlings ready to go in the ground later this spring. I was also about to plant gojii, but as it turns out, I might be allergic to it.