As someone who uses a 5x7" Technika III, I can say that they are heavy! For people photography, I would far rather use my ancient Voigtländer Bergheil 9x12cm at a fraction of the weight. No rangefinder, but a very precise focussing scale.
Handholding a Technika is feasible, and would be the only time I would prefer that over a field camera. Oh yes, if you're going to slam it around, the Technikas can take abuse that would turn any wood camera into kindling.