In terms of just building DNG profiles, the two are pretty close (I actually preferred the DNG Profiles out of PassPort a tad). But as you point out, the DNG Profile Editor is, well an Editor and no such editor exists with the PassPort although you CAN use the Adobe editor with Passport generated DNG profiles.
You can indeed use the DNG Profile Editor to edit any DNG profile, including those made by the Passport software. IMHO there's an advantage to editing the profiles made by DNG-PE though, because you can directly modify the adjustments made by the Chart Wizard. In the case of an externally-created profile you can only add additional adjustments on top of whatever the original profile does. And you have no real way of knowing what adjustments the original profile makes, unless you decompile it with something like dcpTool and go digging through the XML.
What is nice about the Passport software is the ability to build the profiles directly inside of LR (although you have to quit for them to show up, something the Adobe team needs to address like the Photoshop team did years ago. Their plate is pretty full so its not a huge big deal).
The Passport software is certainly more user-friendly, no argument there. That just doesn't qualify it as "high-end" in my book.
What I'd really like to see is a true profile editing solution, where you can open a DCP file and see any and all adjustments, as well as tone curve, etc. Right now the DND-PE is really an iterative profile creator rather than a real editor. But maybe that's not feasible given the way DCP's are structured, I don't know.
