It certainly depends on your likes. We went through the same thing when we bought our Heat several years ago. At the time the Formula windshield was a big plus for us but after a side by side comaprison the Heat cabin space coupled with the sleek lines made it a very simple choice. The 28 Heat is much, much bigger inside. I believe the Formula has a narrow beam contributing to this.
We've never looked back; just went longer.
You'd be happy with either I'm sure but this is the Nordic section