One thing I found is that the reliability issues are usually quite fleeting. I have the feeling that a lot of the people who are experiencing issues are going to the Apple store straight away to get it fixed. I've had a few issues: 5 key stopped working properly, space stopped working properly a couple times, same for f key, where by properly I meant it needed more effort to get the keypress out, however every time the issue resolved itself in 2 or 3 days of use (presumably by the typing breaking up whatever dust had gotten itself under there)

They are definitely unreliable and shouldn't break so easy, but every issue I've had has resolved itself