Hello Krishna,
as we've developed many "core" Web Dynpro applications and many FPM applications in our team I could summarize our experience in this area as follows:
- FPM is overall much faster in the UI-development compared to "core" Web Dynpro
- the fewer interfaces the better - everyone knows where to search for e.g. processing the events => method porcess_event
- where the FPM-GUIBBs don't fit you could always use the so called "freestyle UIBB", which is a "core" Web Dynpro component
- the standard functions provided by FPM simplify the applications => e.g. switching between read and edit mode
We in our team decided to use FPM in every new development. By the way: you shouldn't use the OIF-Floorplan anymore, because new development will be made in the OVP.
Hope I could help a bit.
Regards
Frank