First thing to consider is that most of us have experience only with the old Arc design. However, Tthe new design is supposed simply be an incremental improvement over the old one, so it seems reasonable that we can make comparisons based on past experience.

Second thing to consider is that the previous Arc went under and the new Arc has not shipped any production units yet (AFAIK). The usual buyer beware applies. I hope Peter isn't charging people's credit card until product ships, but I don't know.

In any case, I feel the Arc AAA is much better light than the Photon (and other button cell LED lights) in many ways.

The biggest difference is the approach. The Arc is regulated and uses a power source with much more engergy capacity. The result is the Arc runs at pretty constaint output levels where the Photon starts off strong and then drops off fairly significantly. To really see how signficaint this is, check out the runtime graphs in the posts linked below.

The Arc is also much more sturdy than any of the coin cell lights. It's waterproof and pretty much bomb proof.

The AAA battery format is more easily available and more likely to be cross-compatible with something else in your kit.

You can use alkaline, lithium or rechargable batteries in the Arc and it is very easy to change the battery.

The screw down design of the Arc makes it nearly impossible for accidental activation.

All in all, the Arc AAA is suprisingly small, and a very serious tool and a good alternative to the Gerber Infinity Ultra when you really need something small and lightweight. Run it with the new lithium AAA batteries for even better weight, runtime, shelf life and tempature tolerance.

The other side of course is the Photon is so light as to almost not be there.

In general, if you have space in your kit, the Infinity Ultra can be a better alternative because it uses an even better power source and is cheaper. The new Ultra probably isn't built quite as well as the Arc, but it is still quite rugged.

Here are some posts from CPF:

New Photon Freedom vs New Arc AAA Rev4 Premium

Photon 3 runtime plot by Craig (The LED Museum from this post.

Infinity Ultra G (same as Infinity Ultra) runtime plot by Roy:

This_is_Nascar's comparison lithium vs alkaline showing the benefits of lithium batteries.

This_is_Nascar's runtime plot, new Arc vs old Arc from Re: Arc-AAA beta test and general topics - Part 2 thread.

This_is_Nascar's New Arc lithium vs alkaline from same thread.

-john