Yes. Cable was fast as heck during weekdays or late at night, slow in the evening when the neighbors were home.
Cable usually uses a shared pipe of bandwidth between you with your neighbors. If there's a network bottleneck anywhere, you see it when everyone is home.

I've been back and forth, as the phone and cable companies have upgraded their systems in my area. At first, I couldn't cable, DSL was the only choice, but it was flaky. Later, cable came available but the speeds were extremely variable (but always there).
Then the phone infrastructure was upgraded and I could get solid 40Mbs at my house, so switched again.
I have heard that Comcast upgraded their stuff and the speeds are much more stable than they used to be.

In short, what's best is highly dependent on the infrastructure at your specific location.