I predict that the Arc will win. I carried an AAA on my keychain for over a year. I eventually replaced it with a Leatherman Squirt P4 for two reasons.
1. I figured out that discoloration on the Arc wasn't the finish wearing away to expose bare aluminum. It was brass being filed off my keys, and some of them were getting balky.
2. The Leatherman is very consistently useful. Day in day out. The Arc AAA, on the other hand, is often useless. Too little light output. These days I carry my Arcs in my non-key pocket or around my neck, and grab the one that is best suited to my expected needs. Often the AAA or AA, but more commonly the LS.
The Leatherman's red anodized finish wore more in a week or two on my keys than the Arc AAA did in a year. It's looking real worn now, but that doesn't bother me.
Sorry to ramble. The point is that I would carry the Peck on your keys and put your AAA in your other pocket. Use a BP Mini-Clip to carry the Peck. If there's more to do than snip one thread or open one envelope, I find it better to have an easy way to separate knife from keys.