Your views on Millennial media

Anyone here used Millennial media? I have not seen too many reviews about them. I am using banner ads from them. I was happy with their performance when my traffic was low, but now that i get almost two million views a day. My eCPM is down to $0.20 half of previous, But fill rate is almost 95%. Can anyone recommend a better network other than admob or Inmobi, specially suited for high traffic.
What has been your experience with millennial media?

Generally good performance and they have good ad units including video ads.

Their website is a bit messy, but overall it all works quite well.

Only real downside is that their payment system is net60 on average. Most networks running the same units offer net30-45 typically, which does matter when you’re really pushing out traffic.