The way i understand it is, Diamond Nectar is the "fulvic/humic acids" boost which is more geared toward veg and flower production.
FloraBlend, the way I was told by the fellas @ the hydro store, is that if you use "Grape Fusion" for example, it WILL impart a grapey taste into whatever you put it in. And more like a weird cheap grape hard candy taste. But point being, the FloraBlend works, and quite well.
I'm using Floralicious Plus this run, and I suppose it adds to taste and aroma because my current grow is BOOMIN, but I also had good success without it. But I can't say for sure, at least not personally and not yet.