Hi
I have a pair of 30mm NPLs which I use in a 100mm f6 binocular and they seem rather good - sharp on axis and minor degradation at the edges, good contrast, well made, etc. They do seem better than other plossls I have used but I don't have anything else to specifically compare with except for some shorter focal length eyepieces - eg. Vixen LV and Meade Series 5000. In terms of overall performance for me, they work well. As well, given this (limited) experience, I have been thinking about getting the 25mm version.
Here's one review of the set:
http://www.cloudynights.com/item.php?item_id=1866
I have heard (can't remember where) that the NPLs are repackaged versions of their previous Plossls with better coatings, of which there are other various reviews.
Good luck
Andrew