I have 4 sites 3 are blended with the same color backgrounds as the site but yet the 4th site is not blended was not getting any sort of clicks so curious I tried the default ads with the white background guess what I started get more clicks than 2 sites that was blended could have been caused it stuck out like a sore thumb.
I'm personally not a fan of blended. Ads should attract attention. Be sure to use existing colors though.