I just tried it. It has a good interface, but a massive downside in that it doesn't have any automated importing/parsing of W-2's, 1099's, and other forms, unlike TurboTax. You have to type in every single number, leaving room for fat finger errors that TurboTax largely eliminates. This removes much of the advantage of doing your taxes online in the first place. TurboTax will smoothly import these, sometimes directly from your bank's website (you don't have to download and upload the PDF). If FreeTaxUSA built a robust tax form PDF parser it would be a real TurboTax competitor. Right now, it's just a cleaner interface to filling out the IRS PDF's on your own. It's good if you don't mind a more manual approach to your taxes.

I had a lovely experience with freetaxusa this year.

They're not entirely free, but they're still very cheap and transparent about their pricing. They don't do the login thing where you hook into your banks and pull in documents automatically, but... honestly those aren't that useful and I'm not sure I trust those on turbotax.

Another vote for FreeTaxUSA. They are totally free for federal returns but I happily pay the $6 for the ‘Deluxe’ service level to support its development.

Been using them for years now after getting tired of TurboTax’s $60-100 fear racket.

I don't mind paying for a service, but with a URL that includes the word "free" I was surprised to see at the top of the page "State Returns $14.99 $12.95 — 12 more days to save on state filing"

I've been wanting to try it, but I can't sign up because they, for whatever strange reason, don't allow emails with foreign country tlds...

Only free for federal. Also doesn't seem to be open source so who knows if they're logging your social security number and other info.