I am thinking about picking up a Hilleberg Jannu - anyone out there have any detailed experience or thoughts about it?

Have you seen this thread in the archives: hilleberg-jannu-t49894.html

I have not personally used the Jannu but recently bought a couple of Hilleberg tents. I went with the Staika and Soulo as I preferred the entry/exit to that of the Jannu. If I couldn't have the Staika, I'd get the Allak. I'd suggest seeing them in person if you possibly can.