Well. Sadly I don't have any benchmark (or some serious analysis) to share with you but I can tell you this:

- I pay about 40usd for a non symmetric 12Mbps connection. It works ok - at least for me - I can stream music or watch something on Netflix without any problems.

- My ISP has a max of 50Mbps (non symmetric)

- You can find some corporate symmetric connections (I'm not aware if you can have those at home) but I suspect they are like a regular connection in some other more advanced countries