Ving, you just want someone to be guinnea pig for those sieberts, don't you?
On the subject of reviews on CN, one by Tom Trusock notes coma as being the biggest issue with UWANs in fast scopes, and writes:
"The 28, 7 and 4 were extremely competitive eyepieces even in the fast (f4.5) Obsession with edge sharpness on a par with the Naglers ... I did note a minor amount of field curvature, perhaps most noticeable in the 28mm, but I suspect most individuals' eyes will probably accommodate it with few problems."
So either Mike and John both have very unaccommodating eyes, or Tom Trusock really wanted to like this eyepiece.
... no matter what the reviews say, you won't know till you try... And I believe this guy TT is one of the more experienced people on CN.