The GS645s does not fold - it has the 60mm semi-wide lens and the 'crash bar' on the front. The 75mm lens version does have a bellows. It is happier as a vertical format, but it is no harder to go horizontal than turning a 35mm camera. I use mine as a light travel camera when the smaller negative (compared to 6x6 and up) is outweighed by the convenience of 15-on-120. I would put it in a padded bag. Despite the crash bar the lens mounting is not the strongest ever made.
The meter is actually pretty good. Less prone to flare influence than the one in my Mamiya 6.