Don't know that I'll have much to offer, but as a new (less than a week) owner of a QC700, let me jump in.
My recent experience has been three years in a Mariner Express and I wanted to add a faster boat for distance and group paddling and eventually racing in all conditions.
I'm 5'8" and 230 pounds - close to the ideal weight for the QC700.
My first evening on the water I found the boat twitchy at first, but the balance soon settled in. Two days later I paddled the QC with a friend who was in an older Valley boat. We covered twelve miles in the Gulf of Mexico in 1 to 3 feet chop and a fifteen mph breeze from all points. I had a much smoother (sleaker?) ride than did my partner who experienced more pitching over the waves. Yesterday evening I spent a couple of hours working on handling, sprints, various turning strokes, wet exits and reentries, and rolling.
I was surprised at how quickly the Q700 became not only comfortable, but precisely responsive, given the discussion here.
I think that a big factor in my own adaptation is the hundreds of hours of surf and rough water play in the Express and learning how to finesse its handling with body English. Learning to roll and also becoming comfortable with the Express on its side and using the secondary stability and a moving paddle for support in chop and in breaking waves has helped as well. Several dumps during the learning curve were also educational. 
The seat in the Q700 will have to be changed for leg comfort and I'd like to have less water in the bow and stern compartments at the end of the day. I cannot determine the utility of the skeg - the pivot point moves from under my seat to the stern of the kayak when the skeg is deployed.
Can't wait to try it out in rougher water this winter and keep pushing up the learning curve.
Steve
: Your question (and the responses) actually makes me feel 100% better about my
: current comfort level in my Q700.
: My Q700 seems to take pretty good care of me when I let it (that's the key).
: I'm 205# and have fewer years paddling. Skills sound similar otherwise.
: I've demoed a lot of other 21"-22" beam, but this the only one
: I've owned. I only have maybe 100 or so miles in it.
: I've only dumped it once unintentionally - third time out - in the ocean -
: after paddling 15 miles - last 11 of that in a combination of rear
: quartering and beam seas and chop. The rest was in busy traffic and going
: through a fairly busy port. Mild fatigue (and high heat) had more to do
: with that one than anything. It definitely ain't the boat or I'd be
: swimming a lot more!
: Each kayak certainly has a unique "presonality", and none is right
: for everyone. As you say though, the reactionary response issue is the
: real trouble. Constantly being tense and over-correcting gets tiring
: pretty fast and fatigued muscles magnify the problem. Once your stabizing
: muscles begin to tire - there's no way to effectively relax. Call it a day
: and save it for the next paddle.
: Here's a recommendation I'm amazed no one offered yet: Work on rolling. Once
: you have a passable roll - you will push the edging and bracing more - and
: the narrow beam becomes an asset that should open a range of performance
: instead of being a stability limitation. Even just doing a few attempts,
: wet exits, and other rescues really goes a long way to tuning in to the
: boat and getting the confidence and ease on the water back. If I haven't
: paddled for a while the tension comes back. A few flops and things get
: better quickly.
: Even if you sell it as you now have the Mariner II, the wet effort is well
: spent. Learn to roll the Mariner (since we know you'll have a million
: reasons to only paddle the new kayak) and then give the 700 another try if
: it hasn't sold already (but why wouldn't it!).
: I think rolling may be the only way to get past "it's me not the
: boat" issues without limiting yourself to boats with excessive
: primary stability. Either that or borrow a racing surf ski for a while and
: see what tippy really is.
: Comfort/confidence is required to really tap the speed potential too. I've
: still got a long way to go.
: Kris
