Facebook will go public tomorrow at $38 a share, valuing the social network company at more than $100B. That will make it the biggest Internet IPO ever — and one of the toughest stocks to analyze. Fans see it as the opportunity of a lifetime to own of piece of company that’s becoming central to the world’s digital future. Critics warn that Facebook’s shrewd owners and bankers aren’t doing anybody a favor: Buyers could discover that they’ve been caught up in a faith-based craze over a young company that lacks a track record of strong earnings, or even a clear strategy for consistent profit growth. What to do? Here are some arguments to consider:

Bulls: Facebook is a revolutionary service with a bright future. The social network had 526M daily active users at the end of March, +41% over 12 months. That should continue: Web usage is still on the rise around the globe, and about 48% of users are on Facebook. The penetration rate also should grow; the rate in the U.S. is 66%. Just imagine what Facebook can do when it cracks into China. It’s a solid business: Once people start to use Facebook, they’re hooked. It takes time to build up a network of friends, and nobody else can offer connections to nearly as many people. Facebook has 901M monthly active users, 3.2B likes and comments a day, 300M photo uploads per day, and 125B friendships. Also, buy now because the stock price is going to go out of sight once it becomes clear that Facebook knows how to make money. Social network advertising is in its infancy. Even so, companies are salivating at the opportunities they see to connect directly with strong prospects. Facebook “is able to provide target audience to advertisers with 90% to 95% accuracy given that users’ identity on FB is mostly authentic (5% to 6% of accounts are estimated to be fake/duplicates),” says Sterne Agee analyst Arvind Bhatia. “This is significantly higher than the industry average of 30%.” Mobile advertising also will be huge. Facebook just started to put ads in mobile News Feeds in March.

Bears: Stay away from this madness. The numbers are reason enough to worry: Facebook generated $205M in net income in Q1, down 12% vs the same period last year, on revenues of $1.1B, up 44.7%. The company’s past growth is fine but it will be tough to continue that pace. As for China: What makes you think that Facebook will find it easier than Google or Amazon did to win licenses from officials at the Ministry of Culture, the General Administration of Press and Publication, and the Ministry of Information? The advertising picture also is complicated. General Motors just decided to stop spending $10M on Facebook ads. If Facebook gets serious about loading its pages with ads, then we’ll see whether Facebook users stay loyal. Remember MySpace. Competition is intensifying from rivals including Google+, Twitter, Pinterest, and Tumblr. That’s just in the U.S. — there are a lot more rivals overseas. And don’t bet that the 27-year-old CEO Mark Zuckerberg will look out for shareholder interests. He will control 55.8% of the company’s votes, and clearly warns in the Facebook prospectus that “we don’t build services to make money; we make money to build better services…These days I think more and more people want to use services from companies that believe in something beyond simply maximizing profits.”