You're right - it is DAMN fast. I've seen 1MB/sec downloads.
Yep, definitely fast - although what you just said kinda proves my point. 1MB (large B - bytes) is approximately 8Mb (small b - bits). On occasion, from a good site, I get 1MB/sec downloads on my cable line here. If the site can feed you fast enough, you should actually be able to see 2MB/sec or more on FIOS - there just aren't many sites out there (and/or paths from those sites to you) that can feed you that fast. 1MB/sec ain't bad though!
Or, looking at it another way - if you're in the middle of a 1MB/sec download, there's enough bandwidth left over with FIOS for a second computer to do a completely separate 1MB/sec download simultaneously - without getting into any degradation issues whatsoever.