I recently bought a .Net ( NameUs.net ) and more experienced domainers told me that .net lost credibility in the domaining market with the appearance of other Ltd's. I am new and I can't give an appraisal but this seems to be pretty straight forward and conveys a real message. This kind of domain names is pretty much appreciated.
TLDs (Top Level Domains) are the com net and orgs, ccTLDs (cc=Country Code like .US) and then there are the new ones that were released a few years ago like .law, .horse Etc..
I don't think that .net domains are good enough nowadays as I personally recommend buying .com domains for the money website. As I already use it for my sites.