BimlExpress is a free Visual Studio add-in for working with Biml in your SSIS projects. It allows you to add and edit Biml files, generate SSIS packages from Biml, and the code editor is fully featured with syntax coloring, error highlighting and intellisense.
If you are already using BIDS Helper, you will see that BimlExpress works the same way and includes all the same Biml features as in BIDS Helper – just with a new and improved code editor. No more squiggly red lines, yay!
For normal Biml purposes, I see some benefit. But to me, the biggest benefit is when presenting: a common question which comes up during Biml talks is, “Why does Intellisense say you have so many errors?” A superior code editor is well worth the download.