I've seen little (if any) distortion in screen shots of the thing being used correctly. I have an old school monitor so I only run it at 105 degrees, but even at that level, it really opens up the view, and allows for much easier takeoffs and landings, and it's especially nice for formation flying. I should think that 120-130 degrees would be ideal for a widescreen (and that's what San recommends), and this can be had with little or no distortion. 120-130 degrees should closely approximate a natural field of view (not accounting for peripheral vision).
As for "seeing more", isn't that the whole point? If anyone wants to constrain themselves to some arbitrary limits on their field of view, then they can be my guest, but if I can get closer to what I can naturally see in real life, then I'm all for it. If there was anything unrealistic about it (when used properly), I wouldn't use it.