In reading the Boardseeker review, I too was a bit perplexed by their conclusions. But when I compare it to my experiences (in my case a Quad 86), perhaps there's another possible explanation.
My first experiences on the Quad 86 were lackluster. I was thinking there would just be an adjustment period to board's natural style and I was mentally prepared to let things slide until I found its secrets. But in fact my particular problem centered on the security of the rear fins. On my board the set screws are not really true set screws as they have a slight head to them which prevented their full engagement with the FCS fins. The results was a less than stellar fin security. This absolutely makes the board squirrely. I can appreciate it if Boardseeker simply did not have those rear fins tied down tightly, because I knew the moment when the rear fins got loose, the board just stopped performing.
I have subsequently modfied the set screw arrangement to secure the FCS fins rigid. What a HUGE difference it has made. My last session with the board truely revealed it promised manuevering potential and, in particular, surprised me with its rather impressive straight-line speed.
So I surmise that perhaps the board is fine, but that the fin arragement is simply not rigid enough for the Boadseeker reviewers to unleash the boards potential.