some strange responses about .net here, there is nothing at all wrong with .net except maybe for type in branding or perception for resale, and he is not buying the name for resale purposes it seems, but for seo, in which case .com and .net and probably the hyphenated .com would all be equal (although some people say plusses and minuses for the hypen keywords for seo)
my greater concern for seo purposes is that you are often at a slight disadvantage when you register a brand new identical domain name to one that has been around and established for a long time, google seems to discount a newly registered domain a bit compared to the one that is around when they are equal
example to explain what I am saying: say there is a domain fatnudegirls.net that has been around for 10 years and is sitting #1 in the serps for "fat nude girls", if you now brand new register fatnudegirls.com or fatnudegirls.info, I have noticed that it seems a little more difficult to get a high ranking for "fat nude girls" with your new domain than if that old site wasn't there already... just an observation and of course with seo everything is subject to fluctuate and even change overnight
if you can explain your intentions and reasoning a little more it might be possible to give more exact answers on this one