RPS Asks: Do You Use SLI/Crossfire?

I worked on a PC hardware magazine for years, and found myself as caught up in the bitter CPU and GPU wars that characterise that industry as much as the next man who cares a little bit too much about expensive circuitry, but even so I've never really fancied a multi-card system via NVIDIA SLI or ATI Crossfire. The noise, the expense, the technical potholes...

However, between Rage, Battlefield 3 and Skyrim (particularly the latter, wanting to try out all of the settings tweaks and mods to max it out), for the first time I'm thinking about doing it. I've got a GeForce 560 (non-Ti) which more than holds its own, but there are usually a few bells and whistles I need to turn off if I want a solid frame-rate at 1920x1200. The expense of higher-end cards is extreme, but for around £120-50 I could pick up another 560. Maybe I will, maybe I won't. But have you ever dabbled in the dark art of multi-card systems? And was it worth it?

The below poll is hardly scientific - I know that - but I'm interested in getting even a slight sense of whether SLI and Crossfire are still the domain of fairly hardcore PC enthusiasts, or if they've also been adopted by normals.

(I'm going to pretty much ignore three and four card systems for the sake of argument, because Jesus Christ that stuff's insane.)

IMPORTANT - DO NOT PRESS 'VOTE' AT THE BOTTOM OF EACH QUESTION. CHOOSE ALL YOUR OPTIONS IN ALL QUESTIONS FIRST, THEN PRESS 'VOTE' ON JUST ONE QUESTION. If you've already fallen prey to weirdness, refreshing the page may be sort it out. Sorry 'bout that, we can't find a perfect poll plugin yet.