I love white balsamic vinegar! Like black balsamic, it varies greatly from brand to brand and price range. The brand I like best (I've only tried 3-4, however) is Napa Valley's Naturals Golden Balsamic. I use it often to deglaze pans when cooking with chicken or shellfish. I tasted Napa's side by side with Trader Joe's White Balsamic and wow were they different from one another! Champagne, I haven't tried Alessi's brand, but I'll look for it next time!
I also use white balsamic in vinaigrette, when I don't want the dark color of the black balsamic.
Here is what Napa Valley says about their Golden Balsamic:
"Today, most Golden Balsamic Vinegar consists simply of sugar, and low-grade vinegar that is boiled and stored in stainless steel tanks for less than one year. At Napa Valley Naturals our authentic Golden Balsamic Vinegar (Aceto Balsamico Naturale) from the Modena District in central Italy is pure, fresh and fruity with a delicately balanced aroma similar to Chardonnay. This is a fresh, full bodied, zesty vinegar that is light in flavor and won't discolor food.
Rocktruck, I hope this helps and it would be interesting to hear which brand you have in your pantry,