Mech's are a very misunderstood and feared device, BUT as far as involvement goes, these devices provide the most satisfying and engaging vaping experience you can get.
firstly you MUST know your battery safety procedures, Amp ratings, Pulse ratings, wrap condition, polarity placement and voltage limits.
secondly you MUST have an understanding of OHMS LAW.
thirdly you MUST understand the device you intend to use, is it run in series? parallel? or is it a single battery device, and if so does it run in reversed polarity (like Sub Ohm Innovations devices) and you must understand how each of these configurations behave, also is it a hybrid connection or does it have a 510 connection? these must all be understood before going any further.
armed with these basic facts you are on the start of the most rewarding vaping experience available.
Now i love my mechs, i much prefer them to regulated devices, purely based on the quality of the vaping experience and a bit of vape geekness thrown in for good measure. I currently own a Vapebreed Nookie (parallel), a Hellboy (tube) and a Tesla Invader 3 (ok it's part regulated but it's still a mech), in the past i have owned an Osmium (parallel), SOI Legendary Competition (tube) and a Noisy Cricket (series mod), and at present i am awaiting the arrival of a Batl Mstr from Tower Mods Ph.
when you are looking at what resistance to build your coil be aware that most mechs (parallel/single battery) work best at low ohm resistances .1 - .15 (higher .35+ if you have a series device) it goes without saying that at these low resistances your battery must be suited to the job you are asking it to perform, it must have a good Amp rating 20/30amp discharge rate ideally, and with an ample Pulse rating (25R's are renowned for this) as this is where you are playing on a mech with a low ohm build. Sure you can put higher resistance builds in your device but these will not give the best results, slow ramp up, low heat, low vapour production, if you want to run high resistance builds you should look at regulated devices or series devices.
These devices command respect, if you get it wrong you could end up in a bit of trouble, but with a little awareness there is no reason to fear them, in the end these will give you an experience unmatched from any regulated device.