Sorry to be a downer, but my biggest AI failure has been AI itself. Not worth it to me, as far as time and effort, with having to keep and maintain cleanup bulls. I prefer to let the bulls do their job. Liked the AI results years ago with Charolais. Got some decent Angus calves too in later years, but not all those bulls were all that. Then there was the caveat that different techs were using TAI and timing that is essential was often off and the results were disastrous.
AI is fine if you do it yourself or have a tech that has time to work with you. Avoiding young bulls of the month EPD wonders can help too.
I used Absolute on some heifers, supposed to have been too docility. Absolutely not docile, some of the craziest calves I've ever had the misfortune of having. They were good looking calves though but ended up being sold as commercial calves.
Used Final Product on heifers before his EPD for calving dropped.
Had a tech out to breed some cows and we were discussing the current calves and how one that we all thought was an AI calf was much more powerful than the others. Turns out when we went to register him dna didn't match, he was actually out of my herd bull.