I can't talk you in to or out of anything as I'm in the shopping stage myself, but I'm considering some of the same things, so I thought I'd share where I'm at, maybe we can help each other decide.
My Drunker Tanks have died and my Terminators (the Smoktech Terminator that's a knock off of the Killer 705, not the Rainbow Heaven clone of the Odysseus) are irritating me. I want a new RBA with a tank for carrying around with me throughout the day. I don't want a gennie as the leaking makes them unfriendly to pocket carrying. I have RDAs that I like, but again, they're not great for travel.
I'm looking at the Kayfun Lite, the Russian 91% and the Fogger v2 (not quite the same family, but it's similarish and in the running for me). The Kayfun and the Russian are out for me because I prefer the price and size of the Lite/91%. The Fogger is bigger, but it's much cheaper, so it gets a partial pass on the size.
All of these have been receiving rave reviews from many reviewers.
Overall, I've got the impression that the KFL/R91 is a bit less fussy than the Fogger (and the Taifun GT which the Fogger is based on), but the Fogger has the potential to be almost zero maintenance once you get it set up right (per PBusardo's video on cleaning the Taifun, if that applies to the Fogger - I'm really not sure, but I think it would). The Fogger has a glass tank vs the plastic or metal on the KFL/R91.
BTW have you found the Russian 91% in stock somewhere? I have been looking but haven't found it. I did find the
Kayfun Lite in stock here, but I've never heard of this vendor and I haven't been able to find anyone saying anything about them so far.