.com v .net??

There are several factors involved so it's difficult to say exactly.

Here's an example of following advice like "Google doesn't like hyphens" blindly. I have a pre-owned domain that I purchased at GoDaddy auctions that had 4 hyphens in it. It was originally created by a business owner in 1999 who didn't know better. Over the years the site got links and pagerank. They had a simple, ugly, Frontpage created site to promote their business. They hired a web designer and SEO 'expert' to do them a new site. The 'expert' told them that hyphens in the domain name was bad so they decided to drop their old domain name and buy a new one. Now they have a SEO unfriendly Flash front end website on a shorter, but not memorable, domain name. I have a 10 year old domain with pagerank and good authority links that I can use for various purposes.

In the end analysis what Google cares about primarily are the quality and quantity of your incoming links, how well the content of your site algorithmically matches the search request and some other things like domain age. The domain name is sort of a tie breaker if you're even with another site on almost all these other factors. In that case, the .com without hyphens usually, but not always, wins.