A small update, which could help if you experience a bad connection, poor routing or live further from the servers. All servers now support connecting through SDR (basically Valve's gaming VPN), in addition to direct connections.
So if you are on a server and have packet loss or unexpected high pings, type "!sdr" in chat to get the SDR connect info.
Just paste that in the TF2 console to connect to the same server, but this time through SDR.
As an example, this helped lower my ping to one of the Chicago servers, the first row is me on SDR, with a private SDR IP, the second row is me on a direct connection to the server: