If it is a business directory, then yes it should. My fiance has a .biz directory which is doing quite well.
I'm more of a fan of .net . It's easier to brand and you're not going to be making people think you're an organisation etc. At the end of the day, I'd say it depends on the domain name you want, but I'd always be more inclined to steer towards the .net suffix
BOTW seems to do just fine with a .org domain. If its ok for a leading directory, it probably is ok for you too.
Personally i think theres always an alternative .com you can go with, unless theres a specific reason to use a .org or a .net Although its not mentioned, i would only go for other than a .com say if its country specific, so .co.uk etc