As a Belgian (EU), I love how I can pay them just by sending them money, without all these weird intermediate companies stealing your personal details and sometimes even your money.
To answer some contras:
In my experience, the process takes about 10 seconds before the payment confirmation appears in the destination bank. Outside business hours and for some bank combinations, the actual money might be in a reservation/underway/unspendable state until the next business day starts. You can not cancel the transfer once it's gone, so most businesses don't care about that delay.
Typing the IBAN is a tiny bit annoying. I see QR codes appearing, containing bic+iban+amount+message to autofill. You pay by scanning the QR code and pressing OK.
AFAIK bic+iban+amount+message is all you need to pay from anywhere in the world. The BIC can be derived from the IBAN if you have the right and up to date database, but outside the EU it is smart to know it, just to be sure.
Sometimes, reading HN, I wonder if I should write a loooong blog post about how Belgium does its money transfers(iban) and buys bread (Bancontact). I suspect most of the EU will answer: duh, boring! Meanwhile, the average USAian brain goes poof.