iStick TC100W is better than these two, it has the same RX chip so you will get similar performance, but has two batteries which will provide longer life and can be charged safely into the device with USB because batteries are setup in parallel, will also reach 120W with the new update should you ever need it, lighter and sleeker than the Cuboid, with better finish and overall design and is almost twice as powerful as the Evic VTC Mini, so you get RX performance in an all round better design and form-factor and is still manufactured by Joyetech while being a tad cheaper than your other two options.
You still have to marry your batteries, buying two identical batteries (Authentic Sony VTC4 recommended) charge them together and use them together, treat both as one battery pack they also go together under the same exact conditions.
If you prefer a one battery device so that you do not have to bother with marrying batteries then the Evic VTC Mini is great.
Please note that the Kanger Toptank Nano that comes with the SUBVOD is problematic with Joyetech devices' 510 connection (RX200, Cuboid, Evic VTC, iStick TC100W) i predict you will get inconsistent resistance readings, atomizer short or atomizer not found problem shortly with this setup and will have to buy a new tank anyways.
Details about why this tank will most probably be problematic with any of these mods can be found here, check the posts i made in that thread:
http://vapingunderground.com/threads/subvod-has-no-help-anywhere.195181/