Hey Rob, I’m very new to the forum but I can heavily weigh in on this conversation. I bought an Aero 30 about a year ago and have used it for a wide variety of gigs. My friend bought a brand new Zephyr a few months ago and we have practiced together. I have also taken a Bronze course at AbelCine, which provides both Aero 30 and Zephyr rigs for class.
There are two major differences between the two systems (three of you count the rough ~5k price), and that is the sled and case. The Zephyr sled has one or two additional I/O signal ports, I can’t remember exactly which, and a larger stage. It also has a much better bottom/dynamic balancing system that allows for individual fine adjustments and numerous batteries to be mounted. The entire Zephyr system also ships in a hard case, which is super useful because any Aero owner can tell you the pains of figuring out a proper case situation... Tiffen only offers padded duffel bags for Aero kits. What’s bonkers to me is that both systems use the exact same arm and vest!
As far as batteries go, it really doesn’t matter if you get V or AB. Totally user preference, decision is typically based on what existing batteries/plates you already own for other gear.
Hindsight being 20/20, I would have bought a used Zephyr from this site last year. After some basic accessories and a Pelican case, I probably spent 6k new. Which seems to be the average price for a used Zephyr. Who knows, maybe after taxes I’ll actually do that myself!
Feel free to ask me any questions if you still got em!