Is .com significantly better than .net?

I've been writing content for a site I'm planning to launch soon in a very competitive niche. I have a .net domain ready that's aged about a month. However, I'm starting to think that my hard work will pay off more in the long term if I go with a .com instead. The short term results might not be as good because the domain will be brand new when my site launches, but I'm more concerned with the long term since this is going to be a big site with many pages that I continuously add to. Is .com really significantly better than .net?

Why not use both?

Agreed with Chavox. If it is going to be as big as you are saying, save yourself the hassle of acquiring the domains later. Redirect all the other extensions to the .com

Yes, register both so none of your competitor can get it and then use the canonical tag for .net domain and use same design and content on both sites. In this way, Google will not ban you for duplicate content and both of your sites will be giving you money.

.com, .net and .org are considered to be equivalent SEO wize

.com is better from a type-in point of view. SEO wise they're both worth the same.