Hi,
I depends on the case, I have lately started to use more the animator and the animation system from Unity, which lets you preview the animation, it's a nice feature indeed, and it also allows you to create quite complex rigs without cluttering your fsms.
I'll make soon a sample, showing how I use animator to control UI panels, it's powerful in my opinion, but it has its flaws as well, I give you that. Instinctively, I tend to use an fsm, but I made some reusable stuff, and productivity is on par.
Bye,
Jean