I considered both the 48 inch and 31 inch and the best choice for my needs was the 31 inch. This decision was based on weight and ease of transport and setup. This size is more than sufficient to capture both the panorama distance view and enough background perspective differences while locking in on the focus point selected. My current video and photo capturing devices include a smartphone for quick uploads and a sony mirrorless APS-C model. An upgrade in the future of a full frame will definitely enhance the range of capture when using this glider track.
First to mention is that GVM provides a high quality rectangle carrying bag with durable zippers and material. The internal packaging material has been pre cut to fit all the necessary accessories needed for taking this track on location. I removed 5 of the 6 included coil wound shutter cables and just keep the micro usb cable that is compatible with my Sony ICLE camera.
Second the construction of the glider track is solid with all black powder coat finish and bright blue color aluminum adjustment screws to quickly identify those sections that can be manipulated. Those include the 4 rubber feet, 2 for the pan, focus, or straight track movement, and a locking screw to keep the head from moving. The under carriage has both size camera threads at each end for tripod leg stablizer bars and one in the center. I can even mount two different tripod to obtain an unique recording angle using these different holes.
The controller is simple to operate and watched a you tube video in addition to the included folded instructions to set the start / stop. The controller gives me the flexibility to set a short distance or use the entire track for the shoot. The option to use both Sony compatible batteries or a 12V DC cable that is sold separately to create those multi-hour time lapse shots!