This is just my opinion and admittedly I have not used the Nir. They're close, probably close enough so that things like radiopacity, mounting, undeployed profile, price and personality of the sales rep will come into play. The ML is better than the PS1 but it needs some more work on the mounting aspect. I bare-mount a PS-1 one with lower profile than the ML.
We may be at the peak for slotted tube designs but the stent design is one piece of the coronary stenting puzzle.