As I said before, Modo’s native file format is .LWO. The caveat is that Luxology has added various optional extensions to the LWO file format that includes support for things like edge weighting, n-gons and various other features.
So if you import a modo-created LWO into Lightwave then save the object again from within Lightwave it may get saved without these extra extensions.
Because of this I still model in Modo with just 4 point polygons, for rendering in Lightwave. For people who want to model using n-gons there are work-arounds to make the mesh compatible with Lightwave (ie you model in n-gons, then split them into 4-point polys before rendering in Lightwave).

) I’ve been modeling for over 12 years now most of those years in LW Mod. Since I started working with modo I am MUCH better at modeling. Why? Several reasons, but I will hit on the main one. Edges. It seems silly but having edges and true edge tools is just WAY more intuitive for me. As a result I am a better modeler. My meshes have better flow, I can get out of “problem” areas in a model quickly and I can just “noodle” more easily. It’s a little difficult to explain properly but anyone who has spent a few weeks in modo will most likely agree. There is sort of a “pop point” where all the sudden you just GET modo. At that stage you become faster AND better.