I have a stainless v5 which decided to give up the ghost this morning. I wouldn't buy another one but I definitely recommend them.
Don't be put off though as the only reason mines out of action is from me being kak handed when screwing atties on and I stripped the 510 connection threads :/
You can also use button tops or flat tops in the Vamo as it has a spring on the bottom cap accommodating to both. I now have a mix of 18350 flat tops and button tops as some fit better than others in other mods I have.