To be more specific the bob balances the weight between the rear axle and the bob wheel. This is a sling between two axles and it effects the balance of the bicycle more than a two wheeled cart or the ToutTerran or the extrawheel. On a tandem bicycle the effect is barley noticeable. On a short wheel based bicycle it is very noticeable. The extrawheel cart balances the weight more on its wheel than the bob does. The ToutTerran puts the tung weight forward of the rear axle of the bicycle. Ride the bob with 50 plus lbs over a hundred miles in one day on a tour then try the ToutTerran or the extrawheel for the same. There will be a difference in comfort. Now for practicability the bob is good for the kind of grocery shopping I used it for. I purchased groceries at the grocery store and hauled them home. I have an 8000 cubic inch load bag and a cargo net.