Wow! I havn't wheeled with alot of solid axle yotas in my area but majority of them have never had any problems with the stock birfs. Although I'm sure if you wheel like crazy and a hard a it, its only a matter of time before breaking one. I've seen more front dana 30 axles on TJ's break then anything else. I am really easy on my truck also. I'm very quick to pull a winch cable because I'm so cautious of breaking.
Thats what happens when they go over those big speed bumps at the mall
As for birfs i have seen a few of them go on some of the more difficult trails, then again i have seen 44's, 60's and even a rockwell go by by at the hammers!