I took my 4 foot jib out for a first real spin and it was a blast! As opposed to the steadicam devices I have tried, this will get you smooth, professional looking shots the very first time you use it. This is so much fun to work with and this jib is a real solid product.
The portable side to it is very relative, if you consider the heavy duty tripod and weights you have to bring along... Moving the whole setup is a pain and you ought to take the camera and jib off the tripod before setting up somewhere else, even 100 meters down the road. I picked up the whole thing and walked 50 meters, risking tripping or crashing in the process. I would strongly suggest not doing that...
Leveling is a bitch, too, you need 4 hands and a heavy duty tripod head to hold all that weight. And you need a heavy tripod: my Manfrotto 503 fluidhead performed great.
I had my Sony EX1R still set to DVCAM from a prior shoot and I forgot to set it to HD. That's too bad but the action is just as smooth in SD as in HD :-)