This is a BIG eyepiece. It is the jewel in the crown of the William Optics range and the fit and finish are first class.
Optically the performance is pretty good. These 82 degree eyepieces are inevitably compared to the legendary TeleVue Naglers and it is a worthy comparison. The performance is indeed pretty close. In my own direct comparison, the Nagler 26mm was slightly better than the 28mm UWAN but not by that much. Stars were sharp across the vast majority of the field but I did find a slight amount of colour on the edge of the field with the UWAN that just wasn't there on the Nagler. However this was only evident on the moon or where a bright object like Jupiter was right at the edge of the field of view.
Using this eyepiece is immersive and you can get lost in the star fields of the milky way.
You will like it, but be ready for the large size and heavy weight on your focuser.