I work in a rather large game studio and we seriously looked a Modo but it just doesn’t fit in with our pipeline.
The biggest problem is that we need to use Maya for the skin weighting, texturing, and game export of our characters. Once we add Modo into the pipeline the problem of having a seat for every character artist arises. Firstly, the modelers here do a great job at modeling, but directors always have a vision that changes. In crunch time everyone needs to take up slack and that involves texturers and riggers doing some modeling work. In that case, they need to know how to use Modo, and the license requires they have their own seat. That really cuts into a budget when the character department in total needs about 30 seats in addition to modelers.
Secondly, our modelers and tools programmers have modified Maya so much that it resembles Modo’s intentions of an artistically aimed modeling package more than Modo does. This isn’t a knock at Modo, we just have a tool department (like the majority of cg fx studios and larger game companies) who do nothing but make plugins for Maya.
I think Modo is a great modeler, but for larger companies the cost of seats and training just doesn’t offset the cost. Modo is intended for modeling and does it very well. I think smaller companies (who may not have as streamlined of a pipeline) and individual users will get great use out of Modo.
I just don’t expect to see Modo being used by a lot of companies unless they seek to compete with Zbrush in normal and displacement mapping.