IMO Both Gosac and Gosup are pretty much even, with Gosac your trinket will hit harder, maybe is the difference we need to use Gosac instead Gosup for Single target.
If you are playing gosac KTT is stronger. Sims predict yulon being a better option if you are using a pet. Its not such a canned answer. Also since the duration/ICD of yulon lines up with darksoul (esp AD) you can use it in a way that is a bit smarter than your average APL thus its stronger than most would think.