I have a Fuel Rod that I purchased a few years ago, when they were first in the parks, and it has worked well for us. Once you learn where the kiosks are for exchanging them, it is quick and easy to swap them, and as long as that swap remains free, the Fuel Rod is a fine choice.
Now that they have tried charging a $3 fee to swap them, I would assume that it is only a matter of time before that fee becomes a reality. I honestly don't think that the company's business model can sustain the free swaps for ever, and they will need the revenue from those swap fees in order to replace older worn out Fuel Rods themselves.
If I didn't already own a Fuel Rod, I would not purchase one at this point, I would go with a good pack. I have a 10,000 Mah Samsung pack which I use at home. It works quite nicely, and is built very ruggedly with an all aluminum body. Not a bad choice for banging around all day in your park bag.