It's, next to the Siren 2, the most used MTL RTA out there (at least at the time when the Arse came out). At the time i was in the biggest MTL vaper facebook group, and of course you had people with trouble - leaking (due to topcap - that's an objective flaw in the design) was the biggest one, and airflow being too restrictive even fully open. I'm not gonna argue that it isn't finnicky to build right (mainly because i haven't build it yet - but i did in fact buy it just two weeks ago, hasn't arrived yet), but most MTL tanks are because decks are always minuscule.
At the time i had the Siren 2, and i absolutely despise it. I just could not get it to work for me. I'm not gonna argue that it's a shit tank though: many people like it, the same way many people had the same problems as me. I gave mine away to a friend in germany who wanted to give MTL a shot. Hell, there were people who had trouble getting flavour out of the Prime - and i just throw some kind of resistance at it, with "some amount" of cotton and it beats most stuff straight away. In this case, if even half the owners get good flavour out of it, you saying "the bad reports etc" is implying that every single one of those who don't have a problem with it either don't know what they're talking about, or are lying. I personally don't think that's cool.