Here's my Discover APR reduction thread: http://ficoforums.myfico.com/t5/Credit-Cards/Discover-Rate-Reduction/td-p/4753000
TL;DR... they lowered my rate from 20.24% to 16.49% (16.74% after most recent Fed increase). Note that in my thread my first post mentions thinking it would be a year before I could ask again... further down the thread it was clarified for me that they only make you wait six months. 
Although I don't intend to carry a balance I still plan to see if they will lower it again in March/April once my six months is up. It's truly painless; I chose to 'chat' rather than call and even had they not been able to give me a reduction I wouldn't have complained - the CSR was reallly good.
I must say that honestly I 'like' all of my issuers (so far no issues with any of them, knock-on-wood...) but I'm especially fond of Discover... they are just so darn easy to get along with, at least for me. 
I love this forum! Used chat earlier for my wife, who has never asked Discover for an APR reduction in 22 years. Quick and painless... they offered her 13.49% or 0% for 12 months. Since they recently changed her old Cashback to an "it" and gave her matching cashback, we'll pay our hefty tax bill this year, net 0.13% cash back, and get a year to pay it off at 0%! I would never have thought to do this by chat before finding this forum.
