Look at the Photon Micro-Light webpage. They mention which one has their LED. I believe it is the Wenger Esquire SAK....as opposed to the Victornox. I recall that it is now available with the new white bulb. I think that would be more impressive. I believe the site is
www.photonlight.com . I note that the Esquire is a good knife, especially for attorneys
but the scissors have small serrations which might turn one off, especially for smooth fingernails....but it has a file
I don't generally use them for that so I do not recall the exact effect. If that is a deciding point, and you do not have one available to check, drop me an email. My profile should have it.
I cannot comment on the other factors such as thickness...until I can justify such a purchase.
If you really cannot decide, buy the one of your choice and hook a Photon to it. Actually, that is what my wife did to hers.
Of course, then you have a choice, do you leave it so he can remove it, so he can carry the Photon into court houses, Chunnels(saw a post on that), and such, or do you epoxy the key ring so he has to carry both if he wants the light?
Is he handy with tools and such? If not you can compromise. Hook them together with a Twisty and before you close it slide a section of shrink tubing over it. Then position it over the closure and carefully shrink it for a neat appearance and to avoid damaging the coating on the Twisty. By the time he figures out he has been had, he'll be used to carrying both. You may have to seal the other rings.
If you do not know what a twisty is, see the picture here:
http://albums.photopoint.com/j/View?u=91257&a=665876&p=33202559
The reason for the picture is in my post on ferrocerium rods in the Survival forum.