I use RX v1.3 at work to remove tones and line noise from tele-conference recordings.
It's noise reduction feature works great for our needs. Just this week I used it to remove a constant "beep" tone (every 2 - 3 seconds) from a very important conference call. It did leave behind a slight artifact noise, but the "beep" tone, was totally removed and made the client (and my boss) very happy.