From most polls I have seen on here, roughly 30% of people have keyboard and flexgate issues.
Since numbers started to be thrown abound... some facts:
1. The only large empirical survey on 2016-2017 MBP keyboard failures I am aware of is this
appleinsider article, where they estimate the relative failure rates at twice those of earlier keyboards, at around 12% in the first year (the 2014-2015 keyboard failure rate was around 6%). Now, the important thing is that this is the
relative rate, that is, from X computers that have been serviced, 12% were serviced because of the keyboard problems. Based on very conservative estimates about how many MBP's actually fail in total annually (its less than 10%) and also accounting the fact that people are less likely to contact service if they are just sporadically having a key that sticks, the amount of affected machines is probably somewhere between 5-10% (which is a lot, don't get me wrong! — but not far off overall probability that an expensive laptop breaks down). This is consistent with data I've seen people posting from their companies from reddit and also with my own observations (we have more then 20 of these machines in use, 3 of them had keyboard issues within almost three years of use). There are some who report much higher failure rates (like this
source that claims 30% failure rate on a sample of 47 laptops), but given the small sample size, I'd take it with a grain of salt.
There is absolutely no empirical information about failure rates of the keyboard on 2018 models I am aware of, and while Apple has recently acknowledged that customers continue see problems, we simply do not know what the magnitude is. One thing I do notice is that complaints about 2018 models on these forums are much rarer than of 2016-2017 models. I do not know whether it's because less people own the 2018 model, because its relatively new or because it the improvements Apple did indeed helped.
2. I am not aware of any empirical study on how widespread the fluxgate issue is not have I seen this issue in the wild. All I have seen are claims that all 2016-2017 MBPs have a bad design error which will lead to the display cable inevitable getting broken. Seeing that these laptops have been around for almost 3 years now and I don't see angry masses with broken millions of laptops picketing Apple Stores, I am not sure how seriously one should take these claims. At any rate, the keyboard reliability is something that is certainly more relevant.
