Best Single Family Distressed/ REO List Sources and/or Software

Hello Everyone,

Looking to start some direct mail marketing campaigns specifically focused on distressed properties (Pre-Foreclosure, Leins, REO, etc.) I am looking for reviews and opinions on everyone's favorite list sourcing websites or software. I am familiar with the common ones like listsource.com, realtytrac.com, and some others, but given that this will be something that I am sinking some money into, just want to get some more feedback prior too. One of my concerns is the frequency of the list updates. Are these done daily, weekly, monthly, etc?

Any help or insight would be greatly appreciated. Thank you!

Jeff