Checking out the features of SRB2DB, it seems I mainly use Z-offset setting for Things, Displaying of Floor Over Floors in 3D mode, and sometimes, Convert Sector to Stairs. But I'll stick with this before switching to DB2.
It would certainly make Workbench cooler if it can also have an option to turn flats on and off in '2D mode'. I still don't really see much in this new version. 3D mode looks the same to me.