I recieved my Vixen LV Series 5mm eyepiece yesterday and it is great.
It appears to be clear edge to edge, which is much better than the eyepieces that came with the scope. I looked at Saturn with it last night and was able to clearly see the cassini division, and some detail on the planet itself. The long eye relief is also very good at blocking out my neighbours outside lights.
It does have only a narrow field of view (45 degrees) so I have to nudge the Dob pretty regularly. Sometime in 2007 I will save up and and get an EQ6 mount and put my Dob onto it as I would like to eventually get into astrophotography.