T-1 is far superior to Cable for a few reasons, but for residential applications and simple business apps, there’s not much reason for the extra expense. I can promise you that a 10 Mbps connection on a cable modem is still slower than a 1.5 Mbps connection on a T-1. The problem is not in the physical speed (which is the same), nor the bandwidth (in which cable is superior), but in other problems, specifically: network delay and packet loss.
A T-1 connects from your office directly to an ISP POP (point of presence) and (if on a Tier I) directly to an IP backbone. The physical distance is usually covered in less than 60ms.
A cable routes around the cable ring, to the cable office which then connects either to another cable office or to a T-1 then to an ISP POP and (if they are on a Tier I) directly to an IP backbone. (If you aren’t on a Tier I for a T-1 in either application, you usually hit some sort of core router which eventually gets to another T-1 to an IP backbone, just increasing delay time). The network delay in this varies widely on traffic, but is usually in the neighborhood of 150 – 300 ms.
End Result: Network delay decreases performance by at least 2.5 times, making a 3 Mbps connection effectively around 1.2 compared to a 1.5 Mbps T-1.
Next, packet loss. Tier I T-1s usually loose less than 1 packet in 1000, meaning that you don’t really ever resend information. Cable, subject to higher levels of electro-magnetic interference (ever have lightning affect your cable . . .) looses in some cases 5% or more of its packets, meaning you have to resend more information (thereby taking more time). Recent changes in cable tech has helped, but you normally still see a 2-3% drop-off rate as opposed to .1% on a T-1.
There’s a definite cost difference, but the T-1 is superior for people that need the speed and reliability.
First off, avoid when finances and circumstances will permit, the use of DSL and cable service providers. You cannot count on a speed with these providers and in most cases they will not guarantee up time or a service interruption response time. Personally, I have used Cable services and DSL services in different offices and have experienced the same quality and service issues with each. You will notice advertisements from Comcast and other providers of download speeds from 6-12mbps(megabits per second) and you may be asking yourself how that is not faster than a single T1 line. The reason that they are increasing their speed is because of constant rise in videos being downloaded and watched online. 12mbps sounds great until you and ten other people are put on the same pipeline at which point you are using a connection that varies from .5mbps to 2mbps without any consistency. A far better solution would be a dedicated T1 or maybe two T1s if you have a large office.