We have three computers set up in our house on one network (4 kids) and had an interesting time setting up the proxy to allow them access to the internet from their bedrooms.
We haven't had any trouble with security that I know of - but a firewall is always a good idea! IMHO, if someone wants in bad enough, there is always a back door somewhere. We don't keep any "sensitive" material on the PC's, so I'm not as concerned over security as I am about viruses.
Speed - sometimes lightning fast, both on the upload and download, sometimes as sluggish as a 1200 baud modem. It depends on the traffic (read time of day).
Pro's: Fast internet connection - for the most part - and continuously connected. No dialing in, no extra phone line needed. Good on-line and telephone support.
Con's: Price. At around $50 per month, it is as much as a second phone line and internet service provider. Comes with only one e-mail address, thus forcing the other members of the household to get web-based accounts (hotmail, yahoo, etc.). Extra hole in my floor to run the cable from the basement to my computer.
Last but not least, roadrunner switched from Netscape to IE5.0 as their browser a couple of months ago. Not a problem, except they have selected Alexa as their default search engine/information service, and it automatically opens as a frame on the left side of the browser. I hate this, and have been trying for the last three months to disable it. So far, nothing has worked.
Although the speed is the greatest benefit, we selected roadrunner to free up our second phone line, which is my fax line.
D. Steven Whiteswhite@umassd.edu