I am 6'3" 175lbs. and just bought a 55 this week. I've had it out on some flat water and class II, just to play around. As an all around river runner, this boat is better fit to my size and weight than any other kayak that I have paddled. Other similar boats which I fit in are the EZG 60 and the Jackson Fun as well as some older kayaks like the Z and RPM. However, compared to these boats, the volume and hull design is much more suited to the type of paddling I plan to do in it. I could stern squirt the Booster easily in weak eddylines, and the surfing speed was amazing on even small waves; comparable to old displacement boats like the RPM.
The elevated edges on the planing hull worked great for carving back and forth, and saved me from getting munched a couple of times in the hole that I was side surfing. The only problem that I had was trying to bow stall the Booster. The grooves in the deck allow water to just slide right off, making it difficult to hold the bow under for any length of time. However, this might be a technique problem too.
As far as outfitting goes, the Pro-fit system that came with my boat is great. The ratchets dialed in right away for the backband and thigh braces, while the hip pads were infinitely adjustable with some minicell and a screwdriver.
I would highly recommend this boat for an all around river runner at my size.