It makes me want to drink more when I'm vaping, hiccup, oh wait, I vape more because I'm drinking.
In all seriousness though, I've not noticed any lasting negative effects thus far, which isn't to say that I won't die next week and find that the PG/VG/Flavorings have coated my lungs and suffocated me in my sleep but at the moment, no negative effects that I can tell.
It's been pretty much all positive so far... I no longer stink like an ashtray all day, my home smells clean without smoking in it, I don't know about taste and smell being different, I think chicken still tastes like chicken like it always has and I could always smell my dogs farts unfortunately.
Well, there is one slight negative, when I vape in an air conditioned car it tends to make my throat all gurgly and I'm constantly clearing my throat. Not sure whey vaping affects me like that but that's what it does (we've not had a really cold enough day where I live to see if it's the same just vaping outside when it's 42° or not).
If you were not a tobacco smoker to begin with then I'd just cut out the nicotine all together, no reason to get hooked on nicotine if you aren't already.
I started on 18 then dropped to 12 as 18 was terrible tasting, then dropped to 6 and now bounce between 6 and 12 depending on the brand as some manufacturers now only produce in 3 and 6 but some of my favorites are still producing in 12mg.