I have had two 1500 Suburbans(2003 and 2004) both with over 200k
One, my parents, was mostly a soccer mom vehicle, just sold it, and it probably has a long life ahead of it at 200k. No problems with the IFS at all. 4wd was used at least 1000 miles a year in Tahoe ski trips.
The one I still have, with 33's and a six inch lift(had it cranked to the sky with a 2-3 inch lift from 120-190k of it's life) has 225k on it, and has been towing a 6000lb trailer 2-3k miles a year, off-roading 1k miles a year and other shenanigans since I was 18, looks to be going forever. As for the IFS 8.25 front end, I had a wheel bearing go out at 220k miles, and that's it. I don't have the front cranked all the way anymore with the 6 inch, but it's not mild either.
My theory with the Chevy IFS, is they are strong enough to get through anything a vehicle this size and wheelbase has any business being in, as long as it has been reasonably maintained. After that, it's all dependent on the right foot and thought of the driver. With my 1500, I wish I had the 9.25 for piece of mind, but as I am now reaching 250k miles and the ridiculous things I've asked of it off road, I am starting to think the worry is unwarranted as long as I keep my driving style and knowing it's the weak point of the truck.
Do I wish Chevy had put a SFA in these? Yes, but like every vehicle, it's knowing the weak points and driving around them or putting the vehicle in a situations that aids to its strengths (and all vehicles have this one way or another). Now putting a 14bolt in the rear of my 1500 with locker, I pick my lines over the tough stuff, to rely on that as much as possible (it will never ever break with my power) and knowing the front is more there as an aid than as something to rely on.
I wouldn't even hesitate once, especially at a vehicle with the 9.25, much less the 8.25. However, saying that, i wouldn't put a locker in it.