I can't speak to Insight (I live across the river in Ohio where the cable company is Time Warner), but as to Zoomtown, the service is pretty stable. Stated download speeds are 5mb, but in reality you will probably top out at around 4.25mb if you are close to a C/O. Upload is 768kb and you tend to get close to that speed in real life.
I have the "static IP" option with Zoomtown which is meant for telecommuters who connect to company offices through a VPN, which sounds like the situation you will be in. The static IP address costs $5 or $10 more a month and gives you a fixed internet address. The speed is no different that the "regular" residential connection.
If you don't get the static IP option there is a chance you will get a connection that is "double NATed" in addition to it being dynamic. By that I mean that some of the Zoomtown dynamic IP connections still expose only a private address to the customer, not the real internet address. If you use your own router then you are introducing a second layer of NAT to the picture. This screws up IPSEC VPNs royally, although SSL based VPNs should not have an issue with it. Many of my friends have this regular Zoomtown connection and all but one or two are setup with this double NAT'ed configuration. I think the determining factor on whether or not a regular connection customer is double NAT'ed or not is which brand of ADSL modem they receive, and Cincinnati Bell has several different vendor's equipment in the field. Also, some of these dynamic connections can silently go dormant if you allow the connection to go idle for a certain period of time, which would make things difficult if you are intending to access your home system from a laptop when on the road, or allow some sort of server access (not sure if server access is permitted by Zoomtown residential agreement or not, but as far as I know they don't block any incoming ports).
I had Zoomtown many years ago, and had a regular connection which experienced all these issues. I then switched to Time Warner for several years, and now am back with Zoomtown, but with the static IP option, because I moved to an area where no Roadrunner access was available.
Overall I've been reasonably satisfied with the static IP option, but since I do work over VPNs the 768kb upload speed is somewhat an issue. Unfortunately Cincinnati Bell doesn't offer any faster connection speed at this point. There is rumor of them going to 10mb download in the near future, but I haven't seen anything regarding what changes, if any, are being contemplated for the upload speed.
reply to From Atlanta
Having had Zoomtown for YEARS and recently switching to Insight I can say without doubt Insight all the way.
My Insight service has been as rock solid as Zoomtown and the speed cannot be compared. I have Vonage and the call quality is perfect, my upload and download speeds are better than I expected. Even during the peak hours my download speed is always 8+ and I have been able to get the 1 up at all times as well.
I talked to neighbors and friends that have cable (I have DirecTV) and every single one were happy with both their TV service and their Internet service. I didn't find one person that had a complaint about slowdowns or service outages. That did it for me.
The thing with Zoomtown is, they have been promising speed increases for years. I was actually installed even though I was too far from the CO to qualify. My service was solid, but speeds were low. For at least 3 years they told me that the speed would increase and it NEVER has. Don't put any faith or hope in Cincinnati Bell ever increasing speeds. As long as they are in that 200,000 subscriber neighborhood they don't need to so they won't.
Insight is 10/1 and they have started rolling out 20/1 (I am hearing that it will be 20/2 when all gets settled but I don't know) service that will hit Northern Kentucky later this year or early next. You get 10/1 speed for the same price (price after 12 month intro which both have) compared to CinBell 5/768k.