I lived in Boston until recently & came across New England Vaping Company as a complete fluke--didn't even know it was there--oddly enough, while driving to another shop in Brighton. This was back in June, when I first started vaping. I bought a couple of juices: Nicquid Extra Burst (a menthol flavoring, not really an e-juice) which is VERY powerful and awesome, and a NicVape flavor called "American Menthol" which I liked well enough, too.
I also purchased an MPV iTazte, but as sometimes can happen, it turned out to be a dud. It sizzled and died as soon as I got sufficiently far away from the shop to make it a hassle to return it. HOWEVER, the owners, Jamie and Heleen, were incredibly helpful and gracious about handling my returns/exchange, and I recommend this little place to everyone based on that as well as what has already been mentioned--it's a nice peaceful place to go and sample stuff. Where I am now, there's nothing like that and it's always hit or miss with flavors.