I tried the Logitech G9X. I liked it (definitely comfortable), but it was very cheaply made. The surface materials rubbed off extremely quickly and it died completely within two years. That turned me away from Logitech forever, they just don't seem to have the same quality that they use to.

After that, I went for a Razer Naga. It is a decent mouse. If there were one thing I would change about it - I would make the thumb keypad programmable like the G600 is.