Not sure what you want to know. UG is a good program it was the first 3-D program I really was able to get into.
It can be very involved and the system works really well. They have a package similar to PTC's product but I believe that UG made a lot of headway in the mid to late 90's. Their biggest customer is GE.
The system used to be called uiapt becasue it was based on the apt language for boeing for machining complex airframe parts.
If you were looking for more detail let me know.