Ok... as I have said before... how far down the rabbit hole do you want to go?
my two cents worth:
Different types of Ecigs are....
Cigalikes.. very small, portable, but very low battery life.
Ego-T.. Small and portable. much better battery life, but you're generally stuck with pre-made coils and wicks
VV/VW device.. Not as portable as the previous two. Can put just about everything on top of it except the largest coils. Most batteries can be replaced and recharged as needed.
Mechanical.. A method of hooking the battery straight to the coil/wick. It requires a lot of tinkering and can be dangerous if you're not careful. this can produce insane ammounts of vapor.
Those are generalizations, and there are some that fit in more than one of those categories. That is also the "usual" path of progression. Your next step would be an EGO-T type battery. Cigalikes offer around 200MaH hours of battery life for a good one. EGO batteries can go from 600-1100MaH hours. My recommendation would be to get a Variable Voltage EGO as your next step up. The setup I use is a very clean design, and I use an EGO-T 1100VV mod with a mini protank 2 topper as my "out and about vape". It offers great vapor for it's size. The "tinker" value is fairly low on this by design.. that's when I just need to grab and go to places unknown, I'll take this.
My main is a VV/VW Vamo with a rebuildable Atomizer. I never recommend anyone going to this as a step up, since the tinker value can be very high. If you don't mind the size, you can get something like an MVP, Provari, or Vamo, and you'll have a device that fills a variety of roles in one package. IT can be pretty grab and go if needed, and if you want to tinker with things, they do offer some protection.
Since I have been vaping and tinkering for a while, I do have a mechanical mod. Those can be dangerous and requires caution, since if you have the wrong combination of battery and coil, it could result in shorting out the battery and having the battery "explode". I have a modest build in my mechanical, and it produces enough vapor to have a small cloud puff out and swirl around me when I walk. Since there's not much to it, it's my sturdiest device, and I'll keep it in my pocket from time to time and use it when I need my quick "nicotine fix".
In short, if you really don't mind tinkering, I recommend getting a VV/VW device, since it's the most diverse of an item. To get you used to vaping, try something like an Aerotank, or an Iclear 30B that you can just fill and go when you get everything working. For the tinkering aspect, the current design "rave" is the Kayfun or Kayfun lite, but those require knowlege on how to rebuild coils. Do some research, and use youtube to see what you're getting into before deciding which route you want to go next.