I use one which is white and blue borders.
It can be funny sometimes when people use white typing. Like the other day I saw something like:
This is my opinion on the subject:
I also think:
And it took me a while to realise that they had written in white. I thought they just wrote nothing.
I use Xenforo original because I like a white background and find it much cheerier than the original dark one. I like that you've made Xenforo the default style now. Some might find it bland, but at least potential members won't be turned off by it and they can always change it later.
I have been using Xenforo Blueberries. I too like the white background and feel it's more bright and upbeat. The dark background is hard to read.