Thank you for the question.
I am Optical Cable's account rep and currently discussing your v13 upgrade with Sam and Daniel. There are some relevant changes to version 13, however, the UI change will not be nearly as significant as your jump from v9 to v12. Also, in v13 you have the option to add Monarch Data Prep studio which is a huge value.
Please feel free to call me (978) 275 8315 or shoot me an email Andrew_baldwin@datawatch.com if you would like some more detail.