The difference between a polar and spherical panos are that one looks like a tiny world. That is the polar world. I looks as if you are looking into the world. A spherical world is kind of like you are there looking up. it is kind of like a 'tiny world' that you are looking out of into the sky. The difference is pretty much that one looks as if you are looking down on the world below. Where the other one is as if you are looking up from the world that you are on.
The thing that makes my tiny world so convincing is that, especially with the polar, is that It really looks like a tiny world, It makes you believe that you can just go and stand on it. I really like it because it looks really cool. I think it actually looks like a real world. Another reason why it really could pass as a real world is because of the fact that the trees are really what they are like in real life. Another thing that makes the tiny worlds convincing, in the ones with the portrait, is the shadow. I think it brings depth.