Eventually worked pretty well for me after many years of being hooked on cigs. I tried nicotine gum first but although it helped a lot, it didn't give me the nicotine hit I craved. Tried e-cigs around 2009 and was able to quit cigs for a while but the technology was still pretty new, the nicotine concentration wasn't that high, and the coils and batteries kept conking out, and I got fed up paying for replacements and pulling on a device that wasn't giving off any vapour. Went back to gum for a few years but then they stopped selling the unflavoured 4mg stuff and I didn't like flavoured or coated gum, also I didn't trust the multiple additives and the prices were ludicrously high - about the same as smoking cigs.
So I got me a small refillable vaping pen a year or two ago and that worked beautifully - 15mg/ml nicotine strength, unflavoured, the hit feels as good as anything I ever had from tobacco and I don't feel any need to go back. Even buying small bottles of e-liquid it's a lot cheaper than cigs, and the hardware components are much more reliable so the cost is going down all the time. Cigs used to make me feel sick and make my lungs feel kind of asthmatic, but the vaping pen doesn't do any of that. No stink, no messy ash trays or fiddly lighters. With cigs there's a "need" to finish the whole cig rather than let it burn away to nothing, and if you put it out halfway through then it doesn't taste right. With the pen I can just use as little or as much as I like, and I can often use it discreetly while I'm in public. I keep a bit of gum in case I daren't use the pen. I like the pen's "fidget value" which for me is as good as that of cigs.
I think a lot depends on the person and whether or not you get a good reliable device and an e-liquid you can live with.