The FCC recently conducted a study of some of the top broadband ISPs in the country and measured customers’ actual bandwidth as compared to what the ISPs advertised. FiOS really came out on top.
The report is available on the FCC site. The bottom line, though, is that Verizon FiOS averaged nearly 120% of advertised speed (i.e., more than was advertised) and Cablevision was between 50% and 75% of advertised speeds. Latency (ping) was also heavily in FiOS’s favor.