I am considering purchasing a video mixer. I really like the MX-4 DV Digital Video Mixer because of the firewire input; but the MX-4 Digital Video Mixer is much less, although using old sVideo inputs/outputs.

Is this going to highly decrease quality coming out of 2 Canon XL1s? Most would be used for performances.

Any other ideas on affordable "starter" mixers?

Thanks!

I made a lot of events with my videonics MX1 (using composite or y/c). Usually a 3 or 4 cams setup.
Since the signal comes directly out of the camera, the quality is ok even with 100 feet cable (coaxial).
Since none of the new models is giving more than 2 DV inputs, i think you could try to purchase the MX1 for cheap (usually 300-400$) and try it.
unfortunately i leave in a PAL country and PAL MX1 are very difficult to find.