>Are any of you using the UML in a serious way as part of your development & documentation process? If so, did you learn it through self teaching? courses? seminars/conferences?

I use it extensively for design and analysis. I learned it mostly through self teaching, in the UML Distilled book (before we had the UML Language Ref and USer Guide books). I also had the opportunity to refine what I learned on my own from Kevin McNeish's Mere Mortals Training... the last 2 days concentrates on putting UML to work.

>Where have you seen the most benefit from it? Faster development time? Fewer bugs? Easier maintenance? More appropriate functionality in the developed app?

Less surprises in the middle of development activities, less adjustment to the over all plan & switching gears in the middle of a project to handle something you didnt understand thoroughly.

>Where does it help the most? Class/objects? States? Processes? Deployment? Use cases? Interactions?

For me it helps me the most with defining classes, assigning responsibilities to the appropriate object, and handling Processess cleanly.