Basically, I use Firefly only. I've experimented with Superfly, and bought a few Superfly-only products, but I don't like the look of Superfly, TBH, and it takes so much longer. If forced to use Superfly, I will, but I plan to use Firefly for the foreseeable future.

One reason I'm cautious is that Superfly seems to still be a work in progress. I'm hesitant to buy, say, shader packs, for fear that they won't work after an update.

For things other than shaders, I might buy it if I really like it, but I will probably be using it in Firefly, with materials changed if necessary. I bought Anime Girl, even though she's labeled for Poser 12, but use her in Poser 11.