Went out Friday to test my handloads in my round-top slide, Wonderfinish, full-size steel Witness. Only change to the gun was a Wolf 20# recoil spring. Hornaday says the 155gr. XTP backed by 12.5gr. of Blue Dot will get around 1400 fps. Having shot a lot of .357 Magnum from similar weight revolvers, I can believe it: significant recoil, but quite manageable. Cases showed nothing abnormal, gun functioned perfectly. Similar results for a slightly milder load with 165gr. Golden Sabers, these seemed very accurate.
No 'cracked slides', no 'didn't function', no 'bulged cases', no 'my dog bit me and ran away from home'. One person's experience with one example of the gun, take it for what it's worth.