There are five basic esmoking devices - with many variations.
The e-cigar: looks like a cigar, some have a tip that looks like a cigarillo and others have a blunt tip. These have amazing vapor power and cartridge and battery capacity, but do not look or feel the least bit dainty.
The e-cigarette or penstyle: is about 15cm. (6in.) long. They have a tip that looks like a cigarillo. The atomizer is slightly wider than the battery, so when you look at it in a vertical position, it looks like an ink pen with a cap on it (like the old felt tip pens). This style has the advantage of being more socially acceptable than something that looks like that old stinky cigar people have been turning their nose up at for generations. It still has quite a bit of vaporizing power and a nice battery and cartridge capacity.
The mini-cigarette or 901: is about 11cm. (4-3/8in.) long. They typically have a tip that looks like a combination of the round cigarette and the cigarillo - mostly rounded with a flattened area. In the white color with an orange mouthpiece, these vaguely resemble a very long tobacco cigarette. They are a nice place to start for a beginner, kinda middle of the road. They produce some good vapor, have a reasonable size cartridge and the battery can hold up a good charge for 3-4 hours of constant vaping. You can have the cigarette appearance with the white color option, or a less conspicuous appearance with any other color option.
The super mini: has oh so many other names, but is smaller in size than the others. It is typically anywhere from 8.9 to 10.2 cm. (3-1/2 to 4in.) in length and look very much like the old tobacco cigarette we are accustomed to seeing. Some do come in colors, but white with an orange mouthpiece is the most common. These are very realistic and often times are mistaken for a real cig. Performance drops considerably getting the e-cig this small. The battery is smaller and doesn't last as long. The atomizer is smaller and cannot produce as much vapor. The cartridge is smaller and does not hold as much liquid, therefore does not last as long. All of these statements are as they compare to the models I've already listed. The advantage to these is not having nearly as many people stopping you to ask what that is in your hand and what it is about. Most people never question it is a real cig.
The e-pipe: Looks like a tobacco pipe. Produces good vapor. Has great longevity for battery charges and cartridges. Also comes with a considerably larger price tag, fewer color options, less availability, and a distinct pipe appearance. Not that the pipe appearance is altogether bad - it just happens to draw more attention in public which can be good or bad depending on your point of view.
Now that we have covered the basic differences in e-cigs, you have some decisions to make:
How often do you want to change cartridges?
How often do you want to change and charge batteries?
Is it important to look like a real cig? Or would you rather it bear no resemblance?
Is price an important factor in your decision?
What about ease of replacing parts and cartridges? Is this important?
These questions are to get you thinking. Most people start out wanting something that looks realistic. Soon thereafter, many people find they are increasingly displeased with the realism as the less realistic e-cigs are more readily accepted in nonsmoking areas and the questions from passersby offer opportunities to educate the public at large and the limitations of the super mini - always fiddling with changing cartridges and batteries - become irksome.
All that being said, most on this forum recommend the 901 or mini e-cig to newcomers because they are affordable to acquire and maintain, have the option of realism or a something less like a cigarette, perform well, and are readily available by suppliers both here and in other countries.
I hope this was helpful.
I really must find some way to edit the length of my posts. I apologize to all for typing so much every time.
