I ended up paying Apple more money for an external keyboard and trackpad when the Apple store employee told me that it would take me weeks to get my keyboard fixed. I used to love Apple products, but after my struggle with this issue I absolutely despise them.
Initially, I was skeptical of all the reports about how frequently the issue was happening, and I was starting to believe that it was just hysterics by the anti-Apple crowd. But it was eventually just a matter of time.
First my personal laptop had issues, and I was thankfully able to take advantage of the free keyboard replacement. Then my work laptop began experiencing the same issue, and it's gotten so bad that I had to connect an external keyboard in order to be able to login because I have no way to see which characters are getting screwed up as I type my password.
I keep meaning to take it to the Apple store, but the latest estimates are 5 to 7 days to replace the keyboard and I haven't yet had the opportunity to be without my work machine for that long.
It works. Fixed my 'e' key, fixed my spacebar, fixed all of them. You have to hold it at weird angles but it works.
Apple put out one of the least reliable keyboards in any laptop that was simultaneously the most expensive to repair. It took them 3 years of gouging customers with obscenely expensive repairs before they were willing to actually admit to the defective design. There's plenty of users on HN alone who suffered from it when it broke right after the warranty ended. If you didn't decide to purchase AppleCare, you got to pay Apple hundreds of dollars to fix their own design defect on a relatively new machine while Apple staff pretended to be completely unaware that this was a common problem.
I'm glad their canned air trick worked for you, many others weren't so lucky. Even today, best case scenario if your keyboard is far gone enough to need replacement instead of canned air, it gets replaced with a new keyboard that's just as defective as the original.
If I'm coding with an external screen connected (always hot, regardless of activity), and doing anything that requires the CPU (that never fails to bring the temperature tup massively and the fans to come on all the way up) I will make too many mistakes. Missing letters, things I need to press harder or for longer, etc. It's a massive pain.
Works fine when the keyboard is cool though.