I have the rod. It is very powerful and more than what I would consider a true 8wt - but I understand why they need to rate it as such to handle the huge lengths of line European overhand casters throw. In other words the grains over the first 30' rule doesn't apply to this style of casting.
Hoping to get it up to a 10wt, we modified the blank by shortening it. This made a dramatic difference and now it casts a 12wt intermediate WF line with ease. This experiment is being applied toward saltwater flyfishing in big surf conditions.
For a big river rod, it comes across to me as too fast for traditional Spey casting. It would be a cannon casting with two hands though.
Are you looking for a Spey rod or a two-handed overhand rod?