Their caps aren't half as bad as their throttling. That is what I always run into and get me all worked up.
For example, last night I downloaded Windows 7 DVD from TechNet. It is 3,000MB. The download was suppose to take 2 hours at about 600KBps. Only problem is that I hit the 2250MB cap when it was at 60% done. So they cut my speed down to about 285KBps and it takes now takes over 3 hours to complete.
Another example is watching "HD" streaming shows online. If I sit down and watch 2-3 hours at a time then I'll reach their cap. When this happens I start to get stuttering problems which basically requires me to stop watching what I wanted to see.
For things that I don't need right away, I like their 12am-12pm unlimited use. It would be nice to see others, like Comcast, implement this feature.