Cute Quilt! .... Looks like John Deere meets New Holland!
You have a good sense of colour and design ... go with what looks good to you IRL.
The colours do not really show well in this pic so hard to know.
That being said, my first thought would be to bind with the same as the outer border.
The yellow would cause you to look between the two yellows, which would be fine if there was something there you wanted to draw attn to, but not the case this time round. You want to keep the focus on all of those JD squares in the centre.
Like I said ... go with what looks good to you!