New Trace Geometric Networktool very slow

Just wondering if anyone else is experiencing this:
I'm using the new Trace Geometric Network geoprocessing tool in Model Builder. It can take upwards of 2 hours to execute a trace that takes just a couple minutes when I use the Utility Network Analyst toolbar and set the flags manually. And that's when I'm returning a selected set, even.

Anyone else notice this difference or have any theories on why the difference is so great? Or how to make it quicker?

Thanks
Jake