I really like Octane, I only used Iray for a short time before switching to it and have used it since.
The best thing about Octane is the speed. Its really really fast. Way faster than Iray. It also doesnt use
the CPU to render, it only uses GPUs.
Materials in Octane are a bit tricky. While there is an "auto-coversion" from Iray materials, its pretty bad. Which means you will have to tweak every material in the scene yourself (or create them completely new). The great thing about Octane materials is the node-graph. You have different "nodes" that can be put together to make materials. It will take some time to get used to, but once you figured it out, you cannot live without it, its great. And since Octane is a physically based engine, you can look up real life values of materials you want to create and use those to get very realistic looking materials.
Another thing is skin materials. Octane isnt really the best render engine for skin. Creating realistic skin is rather difficult with Octane. It takes time to figure out how subsurface scattering and some other stuff works, to make skin look good. Iray is better at this in my opinion.
The plugin for Daz is a bit of a patchwork at the moment. Some core features of Octane are not usable and there are a lot of crashes. But very recently Otoy (the company that develops Octane) announced that this plugin will get a complete refactor. This will probably take some time but hopefully it will be more stable and all Octane exclusive features are implemented.
So all in all, I really like Octane. It does takes some time to understand how everything works and understanding the materials but it gives you a lot of creative freedom when you get comfortable with it. I'd say you just try it out yourself. There is a free version of the plugin, which lets you only utilize 1 GPU, but thats enough to see if you like it. If you want to use 2 GPUs you have to pay 20€ a month.
Feel free to ask if you want to know something else