Geoff
Never tried brewing beer with anything other than a 'beer' yeast (technical term...). Interesting thought that. I am guessing with a lager it would turn out quite dry, maybe even like TED, but with an ale that would be a bit weird since you tend to want the malty-ness coming through. Not sure about the flavours that a champagne yeast produces since i only use it in a GB and the strong ginger/lemon flavour would overpower anything a yeast could produce.
I guess the key thing to take in is that a champagne yeast has almost 100% attenuation which i dont believe ale or lager yeasts get anywhere near that, more like 80% or lower.
Thats my misinformed opinion
Cheers
DrSmurto