Mindy, 100% and has only made maybe two mistakes back when she was a Pup...
Diamond, was 100% until she went blind, when the weather is really bad, she gets nervous and often makes mistakes because she is too nervous to be outside too long.
Foster, Mostly 100%, but will, on occasion, mark a spot, esp. if new/different dogs are around... Grrrrrr
Scandal, Not reliable, she will even mess in her crate! I have to be very vigilant with her... It drives me a bit batty, good thing she is so cute! She has gotten a whole lot better though, as I can't STAND dealing with messes that there are no excuse for!
Molly, well.... I rescued her as a 3 year old who had never been trained to go outside, period... She was Pee Pad trained. She is rock solid on them! I have her pretty close to rock solid outside now in the summer/spring/fall... Though I have to pick her up and put her out myself... she HATES being outside, I bet before I got her she was rarely ever outside! In the winter, it depends on the temp. she does poorly if it is say, -20... but not too bad at around freezing. I do keep a pee pad down for her always in case of emergency.