ooh, that's pretty, can imagine it with a SS battery. What do you notice when you change voltages? I'm not really to educated with this stuff. Higher voltages vs lower voltages? There's way too many options. I mean don't get me wrong. I'm perfectly happy with an Ego battery and my Volt X2, but there's so much more shiny stuff out there....
VV (variable voltage) can change the entire playing field for you. Now before I start, one thing to know is the Twist is variable voltage but you only have about 4 or 5 settings so you can change it for some good results but you can't fine tune it like the VV devices that have a Display screen and allow you to go from 3.0 to 6.0 in .1 increments.
3 things that using VV does for me is allows me to tweek how much vapor can i can put out (in some cases I dont want to fill a room with steam, in other cases i do

) It can help me tweek how hard of a throat hit I get (using different ratios of PG/VG in your e-liquid helps this as well) and the most important reason for me is all about the flavor. Some flavors (most flavors) change depending on the voltage you are using. Depending on your personal taste and the type of flavor you might prefer vaping a fruit flavor at a lower voltage, or a tobacco at a higher voltage. I love getting flavors that are a mix of cinnamin and a fruit and vaping it at higher voltage because it taste like a pie that came out of the oven, all nice a slightly warm...YUMMY, and now I take a pause so I can vape some Cinful apple.
Ok I'm back! So anyway Short version of all that is using VV allows you to fine tune the vape for your liking. The Twist is an excellent stepping stone for this it will let you go up to 4.8 volts. I personally went from using a Ego C upgrade that I kept on 4.2 volts to a Lavatube that went from 3.0 to 6.0 with a press of a button, and now I have gotten rid of everything else and primarily using a Provari with a protank.
As I mentioned earlier I have been thinking about getting a twist to use at the pool. If the ego is working great for you and the size is good, then you can either just keep using hat and try a protank on it, or if you do want another device check out the Twist. If you start thinking you might want something a bit more then that make sure to do your homework first. I enjoyed my Lavatube V2 but wished I had either spent a little extra cash to get something nicer, or a little less cash to get something that was equal to it. I actualy found a website last night that was selling eVic starter kits for $85, I also clicked buy LOL!!! but then I saw soemthing else that was shiny, got distracted and forgot about it till now....