I've had mine welded up for a few years now wth no problems to report. I used to drive it daily, but not as much anymore. Yes, the tires chirp sometimes, and the rear wear a bit faster than the fronts, but I'm not in this game for tire longevity.
With a lockright in the front, the rear end pushes in low traction situations and the front end has a tougher time ratcheting around corners. I've only had this happen in deep snow, but it was enough that I wouldn't run a welded/spooled rear end if I wheeled deep snow very often - or I'd get a selectable up front.
Frankly, I've tried to break it with no success. I'm always looking for an excuse to upgrade something, but it's held up just fine. When I get any noise from the rear end (like the clunk that sandrat62 mentioned in his BIL's CJ), I know it's time to tighten up the u-bolts again. I probably do it every 8 months or so. There is a lot more stress on them with a welded diff on the pavement.
As far as high-speed goes, I'd rather have a welded diff than an autolocker ANY day. When I still had drum brakes, the welded rear actually helped my high-speed braking tremendously when it came to staying in my lane. Plus, there's no random ratcheting at 60mph to give you a heart attack.
For my budget at the time, it's been great. In the future I'll upgrade.