I like the seat on the left. That is initially what the bike came with, but a real cheap version. I changed mine out only due to stress wear and breakage after 20,000 miles. So now the seat I have is similar to the shape of yours shown on the right. I wish I had the old seat back.Way more comfortable on your rear ,especially on bumpy roads.The narrow seat seems to only support a certain aspect of your behind. Both are nice.