ditto to Mark's experience; I now leave my Lumagen on permanently to avoid HDMI handshaking issues -
My Lumagen is dvi input (HDMI source > dvi) eliminating the HDMI handshaking altogether - but direct connect HDMI source to display can be a drag at times due to handshaking issues;

I must say my new Apple TV seems to handshake very well however, so maybe newer firmware is better...

ken