I've been running them for a couple of years on a trail only rig, and a good friend also ran a set for a couple years on his trail rig.
Not sure what to say, but I've never regretted buying them. When I did my Dana 60 swap I really didn't want to grind the calipers, and I did not want 16.5's (17's were pretty rare at the time). The 13/38's were about the biggest tire for a 16" you could get at the time and reasonably priced.
They are not a true 38" tall (surprise, surprise) but they were a solid 3" taller than the 35x12.50 MT/R's they replaced.
I'm happy with them on the trail so far, but my friend recently went to 42's so we'll see how well I can keep up. However he has broke every time out since going to 42's (3 trips so far) but never broke anything with the 13/38's.......it's a '78 F-250 w/ 35-spline 60 front, D70 rear, 460, C6, 205, and heavy right foot. I've also had good luck with breakage so far (1-ton K5).
Note: I did buy them used, but in almost new condition, and that setup was top on my list anyway.