Switched power supplies really don't care about the quality of the sine waves that feeds them, as long as they have energy to put into the "tank". On the other hand, video monitors like sine waves, and they may not get along with DC inverters/rectifiers (or even portable AC no-breaks, which usually generates AC from DC).
Sure. And not to get into a contest here, but it all depends on how bad the approximation is and what gear it is we're talking about. It's just something to consider and research, and include in the decision. Clean power plants (and that's got nothing to do with green ;) is always a good thing. Doesn't have to be perfect, just close enough for <insert operational criteria here>. Thanks, Christian ***** "The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers."