Man does that look good! Maybe the piano board keys could be bigger, or less time consuming could be biggish, square, even sized blocks in similar colours to the center blocks. That would balance against the size of the strips in the center blocks.
I did that with a flying geese quilt, didn't have enough fabric left from the geese (green and gold scraps from a sale bin) for borders so just made 7"- 8" blocks then bound it in the darkest green.
Getting the blocks right was not easy as there was no common denominator in the length and width of the quilt for cutting exactly the same size blocks for the top and bottom. I had to make them a very slightly different size but it works. Will find quilt and photo it to post.

I agree with you. The quilt is so pretty it doesn't need the interference of a piano key border. That being said I think it would work if your black border was much wider. But if you don't want the added size, I'd pick a bright color that is your quilt and add a 3" border and then bind it in the black. Love your quilt, I enjoy string quilts so much.

Given that you have asked for an opinion then here is mine - love the quilt, the piano border is in my opinion too much for the quilt when it places right beside it as it is in the picture.

Maybe1day

To my eye, I see the piano keys first, before the pattern. I think I would like something quieter with a black small border to finish it off. Even your favorite color of the quilt would work for the quieter part

I really like it that way. Real pretty.

I like the piano key border, but I also like applique borders on the string quilts. Maybe a simple vine?

If you did put the piano keys on, to use up the left - overs perhaps(?) I think it would be nice with a mini plain border = perhaps one of the nice greens you seem to have there, and then the piano keys outlined in black, and then another larger, plain border after that before you put the black binding all around - my suggestion only.

I agree. I love making this pattern but have never thought of using piano keys. Great idea. I think it would make an awesome binding.

i like the black border with the piano outside. very nice

beautiful, beautiful quilt . nice job