Good to hear your honest evaluation of the Manta...
My experience with the manta is that it's got pros and cons (what doesn't?)...
The debacle started with the MFG, but they are not alone in contributing to it. I'm still not satisfied with the 2 I have and so far they were not worth the cost of admission. Can say the same for all the other 22mm BF atty's I have as well. I'll play a little longer. Maybe try wire with a faster ramp up since i haven't tried that in a Manta yet. My lowest Manta build so far was 3.5 ohm, I'm not interested in going any lower. I run VG Heavy to 100% VG joose and that's not going to change either. If the Manta's can't live with that then they are not for me, can go in The Box never to see the light of day again.
It's a given that in general I don't like 22mm BF atty's. I have never liked larger size atty's anymore than I like long DT's. By default I know that makes the row they have to hoe to win me over harder. While some were close I never had a 22 in the dripper days that could produce the flavor I always look for, and none since the GP PAPS & Heron days that could either. Yes I could run Heron's on the Reos, I have a couple of the 510 Heron adapters for my 4 Herons. But they are also a very big and bulky atty that would have to rely on the hybrid fluff reservoir alone instead of squonking. They'd last as long between fill/batt changes, but what's the point? If I still wanted to use them I'd run them on the 11 GP PAPS 2.1, V3's, X's, TiX that's been in The Box since soon after I bought my first Reo/RM2 15+ months ago. Kind of sad, thousands of dollars in GP PAPS that IMO are as good as tube mechs get and only some of them got used for about 4 months before the Reos put them out of service.
I know how to build atty's right, have been building them for well over 2.5 years successfully, early on including on much smaller toppers that are truly a RPITA to rebuild. The over sized coils are where they have to be to clear the cap, are centered T-B & S-S on the AFC's perfectly but back off the deck edge a little. I could go lower with them, but I can't go higher without them hitting the cap. So someone will say use a smaller coil. Nope. These are my favorite coils now with Scottish rolled wicks that hold so much more joose for my LSDLH's. I run the same size coils/wicks in the tiny little O-16's with no problems, and some of the Nuppin's run them with zero issues as well. I get massive flavor rich vapor out of all of them with these coils, but only so-so from the Manta.