Koch Industries ranks 45th on the current list of major political contributors as compiled by OpenSecrets.org.
For every dollar by Koch Industries, the top ten unions on the list chunk in a total of about $14.
As to what I think of them ..... I'm actually OK with anyone who gives most/all of their money to Democrats, or most/all of their money to Republicans.
The real indicator of corrupt practices is the biggies (AT&T, Comcast, Honeywell, Goldman Sachs, Natl Assoc of Realtors, Northrop Grumman, GE, Verizon) who give close to 50/50, thus making it very difficult to find any candidate who will cut off their access to the trough of tax and regulatory breaks.