Bing Ads, Adwords, or Both for Creating Email List?

So I am looking to start building an email list in the MMO niche. I have a pretty substantial budget and after much deliberation I have chosen to use PPC to build my list as I feel the traffic is of better quality than Solo ads.

My question is which ad network is better for list building, Adwords or Bing? Is one better than the other?

Just a note, I do have quite a bit of experience in PPC and can afford to lose some money.

Both, however Bing will going be to cheap and easy for you, however if you have good bucks in your pocket, the best traffic is at Adwords but at an expensive rate, specially for list creating, they are going to allot you a little low QS so higher costings and Bing is going to be cheap here for you.

I'm doing the same thing right now on bing...the single problem its the very low audience

bing is always keyword dependent. I am not doing this not for same reason.