OP - any update on what you purchased and how it is/they are working?
Thanks for this thread. I am also looking at additional 510 batteries and share some of the same goals and reservations. I am loving the Kodo Pro, and as time passes (and is wasted comparing other options), I keep asking myself, "why are you trying to change something that works pretty well?"
In my mind, it would be nice to have other options. I've looked at some of the ones above, but I'm hoping for good VV (especially for rosin), no or minimal clogging (I've had zero problems with the Kodo Pro), and ideally - one that totally hides the cart (for stealth). However, I'm also a fan of things that are well made, so the Vessel offerings are really intriguing to me (for home use), but I'm on the fence about any that appear to *require* a proprietary charging base - and the description that they "fit most" 510 carts.
Off to do more research.