crash2
-Oh no I picked a side-
For pure strength I'll take good old fashioned serviceable bearings any day. The only reason the old school spindle and hubs break is from lack of maintenance. Keep them in good shape and they'll last for decades. You can't service unit bearings unless you get the newest highest dollar versions. They also make a spindle so you can convert AWAY from unit bearings which to me says a lot.
Also with a unit bearing you can't simply pull a shaft and run it where with a good old packable setup you can.