"So, don’t be stingy: a product with no paying users is (usually) better than a paid product with no users. It’s much easier to upsell to an existing customer than it is to find an entirely new paying customer."

This is generally true, but it seems a bit like applying an Enterprise view of sales to a market of minnow sized budgets. It reinforces app consumers' view that apps should only charge for marginal value, not core value or the biggest value. This sort of "freemium" model leads to basically a market of pure crap with extremely rare gems.

Edit: I'm not dumping on the author, here. Were I to "do mobile" I'd probably take a similar approach because it clearly works.