I had a Venom ARC and sold it. It leaked too much on my face.
I currently own an Atomic Frameless (1st gen), Atomic Subframe ARC, and Atomic Venom Frameless (with the Gummi-Soft skirt, as they say).
The Subframe ARC seems to leak the least of them all, on me.
I compared the ARC coating to a non-ARC mask by putting each mask on in my kitchen and looking up towards the overhead light until I found an angle where the flourescent light reflected off my face and I could see the reflection of the bulb on the inside of the lens. The ARC coating did give an easily noticeable reduction in the brightness of that reflection. So, I believe ARC does work. But, only you can decide of the fairly small difference it makes is worth the extra money.
I also have at least 8 other masks.
I am going to give all the Atomics another dive or two, but I suspect they're all going to prove unfit (for my face).
My current top contenders (for fitting me, so they don't leak) are:
Deep6 Gear Signature
Deep 6 Signature Black Mask
Hollis M-1
M-1 MASK - Hollis
Dive Gear Express Ultra View
DGX Ultra View Frameless Mask | Dive Gear Express®
Mako Spearguns Minimus
https://www.makospearguns.com/Minimus-Mini-Freedive-Mask-p/mmm.htm
Especially you just want it as a backup, I would really look at the Deep6, the DGX Ultra View, or the Mako Mini.
I really can't see spending the redonkulous money for any Atomic, just to have it ride around in your pocket 99.9% of the time.