I have heard the same tales from numerous friends as well. I have shot with their Sony cameras occasionally, but just cannot get enthusiastic about the way they feel in my hands. Light and fragile does come to mind. I like light, but not fragile. I do like real weather sealing also, even though I use a camera body rain coat with the slightest suggestion of need.
I rarely shoot video, and when I do, it is usually with a m4/3 body and lens. Or an iPhone..
I shoot mostly wildlife and some motorsports, air shows etc, so long lenses, major battery life, and cracking AF are important to me, as is dust and weather sealing. My cameras do not lead a gentle life, at all.
One other aspect I appreciate and actually use a fair amount is Canon Factory Service, and their rapid turnaround time. They have rebulit numerous lenses including a 500mm prime for me and I can get this done is less than 7 days including shipment to and from Indiana to New Jersey and back.
I would add here that I recently had to have a Tamron 200-500mm lens serviced by Tamron Service - sharpness or focus seemed just slightly off - Tamron promised 48 hour turnaround and they performed, and did not charge me for the repair of a 4 year old lens either - I did have the documentation of purchase and was the original owner. But the rapid repair and return of my lens was quite impressive - I can recall when Tamron service required 4-6 weeks
How is the factory service for Sony? I have heard mixed reviews for Nikon occaisionally.
I do like the newest Sigma lenses and have my eye on a 14mm f1.8 Art for night shots and stars maybe later this summer before I head to Greenland and central Iceland.