The glides provide for faster drying due to the radius on the glide thus flowing more air.
A slotted GreenGlide provides as much adgitation as any other whilst a Holed glide provides less adgitation but holed glides provide faster drying times. On the other hand lips only provide an "easier push" of the wand so to speak, they make lighter work of cleaning but dont offer the other benefits that glides do.I dont know about Shauns glides as I only use green glides.
I clean some really trashed rentals and the glides clean them BETTER and EASIER and leave them DRIER than standard wands. I would not ever go back to conventional wands. BTW glides also eliminate multijet streaking that is common to 3, 4 5 & jetted wands.. Belgium wiltons can be cleaned in confidence and in ANY direction with NO effort. I glides were £500 they would still be worth it. IMO.