Not difficult, once you get used to battery handling,. But what I've found is that the more I get accustomed to regulated mods, the more lacking that mechs seem -- they can be real "fiddly," and have no screen to tell you why they're not hitting right, which they often aren't, because of the "fiddliness". I guess if you got used to them back when they were the only alternative for cloud chasing, then you like them, but otherwise.... it's like using a slide rule instead of a pocket calculator, or doing your books in longhand rather than using a spreadsheet -- sure, you get to the same place, but it takes a lot more fiddling around.
People say a lot of stuff about how straight DC current is "smoother" than the PWM current that regulated mods use in order to step down.... but I can't tell a single bit of difference. A vape is a vape; how the power gets to the coil is, to me, irrelevant. Even the slight "rattlesnake" sound that sound mods issue at low power, is really not a big deal. But I guess a human mind can make it one.
Andria