I would honestly like to say that I love screen spanning doctor. I have a iMac G5 17'' 1.8 connected to an ultrasharp 20'' dell widescreen flat panel. I love it. I cannot say anything about the risks however because I have never encountered one. The forums in the website make it seem like the chance of it messing up is great. I would recommend it, now that I have two, I would never go back.
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iMac G5 rev b. 1.8 2gb ram Red iBook 14'' 800 Mhz G3 12'' iBook 1.07 G4 12'' iBook 600 Mhz G3 3.46 Intel Core Duo 2GB ram 500 HD 24 inch dell flat panel Dual GeForce 8800 GTX in SLI