Hello,
I've a NitroSurge device. I use it a bit, but in truth, not a lot. I've possibly used to 100 times, since I bought it, about 15-18 months ago.
Whether it was worth it or not, is debatable - the pints look good, but I'll need to use it more, to justify the cost.
However, what I have noticed, it's that the pint size cans are often on special offer, which I assume is Guinness discounting them, to try and get more people buying the device and then being "hooked" on the pint size cans. Whatever about the long term, in the short term, that's gotta be a win for the consumer.