A T1 is equal to, or in some places, slower than, cable or DSL. It really depends on the game that your playing, but if you are lagging, you should see if you can get Cable or DSL instead.
You will also find that your internet provider will never promise you a certain level of bandwidth (unless on a leased line), in most cases, they will tell you something like it's "about the speed of a T1".
Also-- if they tell you it's a T1 for everyone to share, then you won't get much out of it, it will crawl depending on how many people use it. But if they say, "you should get about the same connection as a T1", that means that they have alot of bandwidth for everyone to share, and if you split it up equally, and figure everything in, you should get an average of a T1 (1.544 Mbits/s)