Mine is working out just fine. I do have a 5" 629 as well, and comparing the two with full house loads shows the difference that weight makes. Recoil is down-right heavy with the 69 and not so much of course with the 629. But the grips, albeit ugly as they are, that come on the 69 really mitigate the recoil. Especially the forward part that intersects with the trigger guard, totally prevents the knuckle rap that's so prevalent with heavy .44 loads. They're that good. Wish someone would make up a duplicate in good walnut that would feel as great and look 1000x better.
I think Smith did a great job beefing up the L frame to handle that kind of recoil while still making a relatively light, easy packing gun. I've run over 1000 rounds of varied loads through mine so far with no discernible loosening. If I were to run only heavy magnums, and a lot of them, through it, I can't speculate on the result but Smith has no doubt run a destruction level number and still offered the gun to the shooting public.
For me, I run Skelton's old 1050 fps load most of the time (240 gr LSWC with Unique doing the pushing). It's a fun load, easy to put up, and will punch right on through a KY whitetail hit behind the shoulder. Son #2 has put two of our elderly horses down with head shots as well and penetration was over 12".
Another facet of the 69 that sometimes doesn't come out well in reviews is that it's the same weight (within an oz unloaded) as my 4" M19 Smith. As such it makes a great belt gun for daily tramps down through our meadows here on the farm. It's got a good S&W SA trigger as you'd expect, but the DA pull is somewhat heavy compared to the 19 and to several other Smiths that I own in the bigger "N" frame. It's gotten better over time, but I'd still like it reduced some more.
Accuracy has been outstanding, both with jacketed and surprisingly, with cast lead alloy bullets as well. I read a piece by Brian Pearce on the 69 when it first came out and he said he'd had trouble getting good results with cast bullet loads. Leading being the issue. That's not been my experience at all. I size my home-cast wheel weight alloy bullets to 0.430"-0.431" for both Smiths and get no leading even with plain based types up to 1100 fps. That's more than enough for daily practice or casual woods plinking, but still stout enough for anything I'd be likely to run into hereabouts.
With Magnum level velocities, I generally use gas checks or jacketed bullets and have shot the latter up to 1350 fps with fine accuracy. To date, I expect to get 1.25 to 2.0" gps with most any load. I've used Unique, Herco, & 231 for the low end stuff in both .44 Special and also in the longer Magnum brass and get 3-4" gps at 50 yds from rest with no problem. The faster Magnum loads do equally well, accuracy wise, with Lyman's 429244 GC doing an especially fine job, along with 200 and 240 gr Hornady XTP's. The latter with 296 or 110.
For looks, I wish S&W could have dispensed with the IL and the ball lock up arrangement for the yoke...but it makes the gun that much tighter in lock up I guess. And the sleeved barrel looks a bit odd from the front, but that's not the end I look at when shooting. For me, here at this point in life, (pushing 71 this coming May) it's function over form every time...as Whelen said so many decades ago, "only accurate guns are interesting". That's a truth be told. S&W has achieved that in the M69 and in a package that's a mite easier to tote on the gun belt.
Here's a pic of the 69 with the 629 shown for size comparison. The 629's grips are similar but just don't feel as comfortable as those on the 69, but work equally well in handling recoil.
Best Regards, Rod