John,

I have the 3.5mm, 10mm, 14mm XW's I haven't noticed chromatic aberration in any of them, but then again it maybe my in-experience, if it were pointed out to me that maybe different. I do find with the XW's if there is a fault with them it is eyeplacement. When I first slotted the 14mm I must say at first I was a lil disappointed. It appeared a tad out of focus towards the edges. However after playing with the eyeplacement and adjusting the eyeguard this disappeared. All three are tack sharp to the EOF in my f/6 newt.

Have you been able to try the 2" 30mm XW?

And what about the nagler 26mm t5? does it suffer the same field curverture like the 31mm t5? I did like the 20mm t5 of Houghy's so maybe they might be a better option for wide FOV views.

regards