Okay, I just want to be sure I understand this. Your dad's CZ has been 100% reliable over the course of a couple thousand rounds, but it's too 'fragile' for 'defensive purposes.' You hold this opinion because you saw a different model CZ fail once after a few hundred rounds of rapid fire. (Which makes me wonder how many rounds you think you'll have to fire in a defensive situation, but nevermind.)
Your XD has failed you four times in over 4,000 rounds, but it is reliable enough for 'defensive purposes.'
Uhm hmm. Okay. I don't think anything more needs to be said here.