Guinsoos is ok on Shyvana but not great. It is way too expensive and she uses barely any of the AP. Especially early if you decide to go bloodrazor and have a pick axe and blasting wand as you try to build which feels horrible.
You're better off getting BOTRK for the active alone. I play a LOT of Shyvana and have tried mostly every build there is. The one I use the most right now is Mercs, Warrior, BOTRK, Phantom Dancer, ZZROT, and Deadman's. I hate bloodrazor too and mostly refuse to buy it getting my attack speed from phantom dancer instead which also gives me crit and movespeed.
Also, this is the weakest Shyvana has been since release. I can't imagine they won't get her a buff at some point.