Have just tried a sample of the retention+ and i have to say i was really surprised. The white was a lot brighter than NSI that i have been using, and i couldn't believe how well the product went on. building the apex was super easy and its true what you say files away with ease. Love it. Smile lines i have struggled with if a client wanted just a small free edge in acrylic (no problem with gel) but this went on no prob. I can't believe how well it performed for me. Has anyone else found this when they converted from NSI to cnd? On the phone tomorrow for a converstion course. Does anyone Know if Liza still does it in Sittingbourne? Can you do a conversion in a one 2 one?