I recorded this tonight during a round of Pipeline. After which we played Thunder Mountain and it was still happening. I quit half way through because it was getting to a point where it was just not fun. I then tried a few other servers just to see if this was me or not and sad to say I could not replicate the problem. When I asked in chat again this evening people were complaining of the same experience.https://www.youtube.com/watch?v=4PS2ygEAk_Q
In the video you can quite clearly see how jittery it is. Animations are not smooth, walking around is not smooth. Playing a class such as Soldier you would notice his reloading rockets animation would keep repeating itself (you can see it when I switch Medi guns as well).
Just for testing, I have messed with the cl_interp settings to see if this was a cause but each change produced the same results, even the default ones.
Some details about my connection
ISP: Virgin Media - 150MB (though I was previously with Sky 20MB until about 3 months ago, but the problem existed even on that ISP)
I notice you guys are also using an sv_maxrate of 30000 which I think might be the cause or a cause. 30 is usually the setting for 24 slot servers, 40-50 being preferred for higher slots. Especially on an instant respawn where there is a lot of constant battle happening. Worth a shot?