Caudillo,
It ain't that simple unfortunately!! In general, depending on weight, etc, setting a VS that results in a profile of much more than 3 degrees will result in an increasing airspeed, even with spoilers. The only real exception to this is if you have already got plenty of drag devices out such as flaps and/or gear. In this case setting a high VS and using spoilers can be very useful indeed. Intercepting the GS from above after porr vectoring would be a typical example.
Open descent is useful because it prevents any speed excursions during the descent. With a high VS, if you are not paying attention, you can quickly exceed flap or ATC speeds. As I remember it, if you are say, attempting to intercept the GS from above and the target altitude is above the current aircraft altitude, exceeding VFE whilst using VS will result in a mode reversion to OPEN CLIMB!! Very embarrassing when you start to climb at full power!!
As a new twist to the original question, what is the generally accepted best method of recovering the profile? Let's say you are at 250 knots and suddenly given a shortcut. Should you stay at 250 knots with the speedbrake until you level off, then reduce speed and confirgure, or reduce speed first, configure, then descend as quick as you can??