Not really advisable sitting on any OTC long term..although ECIG is not your normal OTC. Trade it would be my advice. PR's likely here till March vote and an increase in PPS also likely.
Seems to me that in a situation like this, one idea could be to trade around a core position, ie trade half your stake, that way you could reap any benefits that come from any short term move up and end up having 'free' shares that you can leave in for that 2-3 year period (whilst retaining your initial investment to invest elsewhere). As always use money that you can afford to lose, GLTY. JMO