replacing old oil clunker boiler

 what do you guys have for a favorite boiler replacement for an old clunker. If someone wants to replace an old oil fired boiler in a non emergency situation,; what would you choose. and how much less oil would you expect to use. my guess would be a little less than 10% or at best maybe 15%.

       Ocasionally I'll do a boiler replacement and I've always gone with a buderus with a riello burner. what are your favorites.                     thankyou

                                                                                   dennis