Following up on this:

Out of the 150 networks currently in the servers list, only four of the major networks have proper SSL support. Forty of the smaller networks have proper SSL support. And sixty other networks have SSL support with invalid certificates. The rest do not have SSL support.

I am considering making mIRC prioritize IRC networks that have proper SSL support, ie. when a user first installs mIRC, mIRC could choose a default network from one of the major networks that have proper SSL support. Currently, there are only four: DALnet, Freenode, OFTC, or Rizon.