0) worse when it comes to developer bottom line (if you are being generous, try to provide enough trial time and usable software during trial period, a large chunk of your users will just never pay);
1) worse when it comes to user experience (you are interrupted, you encounter blocked-off functionality, which basically means that upsell is part of core GUI);
2) worse when it comes to developer experience (now you don’t just program one great product, you also have to program into your core GUI the upsell—the various ways in which it becomes restricted while remaining usable);
3) worse when it comes to product improvement (the unhappy user will simply delete the software and you’ll never know what they didn’t like);
4) exactly identical when it comes to honest paying user’s expenses.
No doubt, there are worse options. (One that takes the cake: advertise it as free software, but constantly upsell the “full version” offered on subscription basis.)
What’s that better alternative I’m comparing free trials against, then? Simply offer returns. Buy it, get a license, make your trial period however long you like; don’t like it—request a refund, get money back, get license revoked. What it means is that “tried and not bought” is no longer one of the “happy paths”. As a result, you have a better chance of really understanding what was wrong (if I must ask you for refund, you are in touch with me), and you also exhibit more confidence in your product up front.
I believe App Store in fact works this way. If someone’s thinking about distributing there and feels like the only way to offer a trial is IAP, maybe reconsider: you don’t need that overhead, one fully featured version is enough if your users can already get their money back if they don’t like it. I believe refund process happens automatically for you as a developer, though I’m not sure whether or not the feedback they provided will be forwarded to you. Willing to be corrected.