I've tried a 31mm t5 nagler, and I have to say I didn't like it. It was excellent
locked onto something, but as soon as you start to scan the sky the field
curverture did my head in. Actually it made me quite wooosie. I had actually
intended to buy one, so I'm glad I got to try before I buy. How ever I did like
the 20mm t5 and I'm hoping the 30mm & 40XW are as good. I have heard
though that the 40mm XW has similar field curverture to the 31mm t5, but
dont quote me on that. But in my scope I could almost fit the whole Veil SN
in the FOV .... going to have to look at 2" filters especially if you astronimiks

So far on the whole, I prefer the XW's over the Naglers I've tried, I find them
just a lil more contrasty and hence more clarity in fine detail, you can list
everything else after that

regards,