Just wondered if anyone has this combination installed? If so, how did you choose to configure the video switching feature of both systems?

Both systems have audio and video switching capability. I'm sure purists will say to keep A/V feeds separate and pass each one through as few devices as possible, ie video feeds to the scaler and audio feeds to the 990. But has anyone here experimented to see if there is any noticeable degradation in using one device as a primary switcher? Recognising that the 990 needs a component output to the scaler anyway, I'm particularly interested in the video aspect of this.
Thanks!