After the first vape on my V2 I put all my other PV's away. With the right amount of nic, 5v can hit as strong as, if not stronger, than an unfiltered analog and some cigars.
One needs to keep in mind that the switch is a "mechanical" switch, and remember that all things mechanical need preventive maintenance in order to prevent malfunction. IMO I would follow jingleballs' and others Noalox or Oxgard recommendation and make that the very first thing to do. At least put some on the button ring resister, the small aluminum ring that bridges the contact points in your switch. Aluminum used in electrical applications is notorius for oxidation, and oxidation is, IMO, the leading factor for all the V2's switch problems. From my own experience and what I have read here about other's problems, leads me to beleive that the V2 switch problem is a progressive problem stemming originally from preventable oxidation occurring on the resister ring.
In my case, my V2 fired optimally and flawlessly for about 3 weeks. After 3 weeks I began to notice a degradation in performance. That is, it would still fire, but the hit was progressively getting weaker. New batteries and atty didn't seem to help. This was, in hindsight I am sure, due to oxidation on the resister ring causing a weaker current. My knee-jerk reaction (shared by many) without thinking was to apply more pressure to the button, which I did and continued doing for several days. Allthough this apparently helped some, it ultimately caused the o-ring to become damaged to the point where there was now enough wiggle room for the ring resister to get askew (catawomper) on the button shaft to where it was no longer flush with the two contact points when pressed. Thus a weak current problem had now progressed to the point of a NO current problem and thus repeated misfires.
For anyone who has had their V2 for awhile I recommend taking the switch apart, polish (at a minimum) the ring resister with something like a fingernail sanding board until it is smooth and shiney, blow it off good, and then give the ring a light coat of Oxgard or Noalox and reassemble. For preventaive maintenance, repeat this procedure at least once a month or anytime it appears that the current is growing weaker, and NEVER apply more than normal (read: light) pressure to the button.