I deliberitly dont read every person who responds, so I don't know where this weather sealing thing came from, but I guess it's probably the usual "wonderful" attributes of 35mm, maybe even a nod to the Pentax and saying traditional medium format is not as good, regardless of what the original thread's intent is.
That's seems to be all this forum has been about for what seems like forever.
Anyway, real life real use, my digital backs are not fragile.
I've used them in the summer in Brazil, Jamaica and Dallas (Jamaica won as even the strobes started blowing and we had to put duct tape over the open outlets) but I only had a slight issue with the leaf back, but it wasn't overheating, it was a bum cf card. We still shot the gig with the Aptus.
This was Jamaica
I've used them in the winter in Moscow (twice), Seoul (twice), Chicago (3 times), New York (more times than I remember) and no issues.
I've shot them in the dust of El Mirage (that's dust) and in Brazil and Mexico. Once in the Texas plains and man that's really dust.
In fact the only repair I've had on my digital cameras is two Nikon mounts came loose (dcs 760/F5) and D3. Lost 4 shutters on Canon 1 series cameras and one sensor.
My Phase backs have gone around the world twice and never gone in for repair. My Contax for 2 repairs, both shutter related, both user error where someone put a thumb through the rear curtain.
My Aptus went in twice once for a bad lcd and once for a digital board, both fixed and returned in three days, door to door.
Shooting an ad series north of miami, with our p30+ I got hit by a wave that submerged me, moved me at least 5 feet and slammed me into the reef, I was completely wet head to toe and we dried the camera Phase/Contax off and kept shooting. I used the camera 6 minutes later and still use them today.
This was about 15 seconds before the big wave hit me.
Now I'm not claiming it's weather sealed but I do know my digital backs are reliable and very, very strong and I sure as hell don't baby them.
In fairness I've shot a trillion more frames with the Canons than medium format, but I don't think 35mm is one bit tougher than the medium format backs.