Well that is a surprisingly difficult choice - both look excellent. But I think I'd give the nod to silver by a small margin. They pull out the silver trim on the bike nicely as if they were customized to the bike where the black ones tend to just look "standard".
It seems that the silver really keeps the lines going by complimenting the frame and the silver shroud. The black bags are too much for my eyes. I do however, think you have a decision that has no wrong answer!
I just got my Cool Lime Green trim pieces in from Kawi today to replace the black. I have what they call Matt black trim pieces on my V35 bags. They are shinier than the rest of the case but not glossy like the paint on your bike. I may sell the black trim pieces if I like the green on the bike. I'll get back to you in a couple of days after I have a chance to put on the green pieces and look the bike over. Let me know if you are interested.
OK, I decided I like the green trim panels on my bike. If anyone is interested, I'll sell the black I have for $35 shipped in the USA. Like I said previously, I have what they call the matte black not the painted gloss black. Not my picture below but it gives an idea of what you would get. I only had the bags on for about 100 miles before I changed out the trim panels for green; no scratches or dings.