My company uses FIOS for hosting many services, like this blog, and so far its working out very well. Granted, I don’t think its as good as setting up servers in a climate controlled, battery and generator backed up co-location, but for the price of the bandwidth and the availability of space, I can’t beat the price.
The major issue with it is the price of IP addresses. Verizon charges very high prices for them, and in my opinion, they should not. Thankfully there is hope, constraints like the one-ip-per-ssl-certificate are getting lifted with the help of gnutls.