a regulated mod has the features built in, the voltage stays the same from beginning to end and that also usually means its more time between battery changes. there is also a wider range of resistance. if you like thinner wire at 3 ohms no problem or maybe thicker wire at 1.5 ohms still no problem. there is much more flexibility this way. and of course there is the safety features.
a mechanical has nothing to break, it is the atty basically attached to the battery directly. the vape seems stronger and smoother to me. pure DC really makes the vape experience different. but i have to build coils in a small window, I stay around 1 to 1.2 ohms.
the reason is with a fresh battery the vape is really powerful but slowly dies off as the battery wears out. i still get a great vape down to 3.5 ish volts
I take my mechanicals everywhere now, love my provari, still never give it up but the mechanicals are as beautiful to look at as they are functional. and it just seems nice knowing i really really have to abuse it to make it not work, a couple good batteries and off I go. sitting around the house though i have a 3000Mah in my vv so i can just sit around and chain vape myself silly - Like Ronco says "set it and forget it" lol
on my mech is a kayfun. in my kit is 2 dripper (in case i blow a coil) a bottle of juice and 2 more batteries just in case.
juist comes down to what you want, and what your willing to trade off. i like my vv but i love the class a nice mech has.