Floor press is a great movement, for most guys it somewhat mimics a board press, depending on your stroke etc... great power movement, almost all the great benchers of the past -Kaz, Arcidi ,Mendy, McDonald, Pacifico , Weil, etc.. all said floor presses were a main staple of their training- Louie, Metal Militia, Kennelly, Bryant also swear by them--- so their must be something good about them !
Most guys I have worked with or talked to found their floor press maybe 25 lbs. higher than flat bench- not all but most did
Just my 2 cents