You can now collaborate with others when creating a Form just like you can with Docs, Sheets, and Slides! Need to work with another teacher on a Form? You can now work on the Form together at the same time--include the chat on that, as well.
One of the biggest changes is where the data will be stored after a Form is submitted. In the old look, a Spreadsheet is automatically created. Now, you have the option to choose the response destination. You can create a new Spreadsheet (like in the old version), place the data in a new sheet in an existing Spreadsheet, or you can just keep the responses in Forms.
Check out more details here.