I'm the opposite -- Never had a bad experience with them. The Taylor machines always seemed to work and stay in tune just fine. That being said, I love the smoothness and the 1:21 ratio of the Gotoh 510's and have them on 5 Taylors in the collection. I want to put them on the K65, but am having a hard time justifying the high cost of a double set when the Taylors are working fine.
In contrast, I have Schaller Imperials on a Hamer Newport custom and, to be honest, I am really underwhelmed by them. A lot of play/slop in the tuners' action and low ratio make them a prime target for replacement if it weren't for the fact that I want to keep the guitar 100% original (It is the actual guitar used in Hamer's final print catalog issued in 2007 before being purchased by Fender a year or so later). Besides, other than the tuners, the Newport is an absolute killer instrument!