I've ridden to both but haven't as yet traveled the Blue Ridge Parkway in its entirety.
Getting through Maine and the route past the border to Nova Scotia is fairly straight with not a whole lot to see and do.
Moose fencing and tons of wildflowers with ever changing scents is about it.
Be careful with fuel consumption as there are long sections of roadways with no gas stations.
Once you get to Halifax it becomes fun and I recommend you spend an entire day there.
I arrived during a "Tall Ships" festival which I really enjoyed along with a few dozen oysters on the half shell and quaffing down a pint or two at each of their breweries.
There are a few very nice hotels right at the harbor and I highly recommend you stay at one so you can walk around, drink, eat, and be merry with a more relaxing atmosphere. (In other words, don't drink and drive)
The Cabot Trail was very nice and I'm happy that I've experienced it.
Ride it counter clockwise to maximize your views.
Traffic, while I was riding it, was minimal which increased the fun factor for me.
There are also other "trails" to ride in Nova Scotia if you have the time.
I enjoyed talking to the people of Nova Scotia as much as I enjoyed riding on their roads.
I found everyone whom I talked to very, very friendly and sometimes hard to understand due to their heavy Celtic accents.
If you've ever been
arrested in the states on DUI (that's how they word it), you'll most likely be turned back at the border.
DUI in Canada is a serious offense.
They take people off of tour buses at the border and send them back to the US.
I've been to the Dragon twice on two different bikes and enjoyed the experience even though Zoom-Splatt traffic was high and Tennessee State Troupers were everywhere.
If you like being around LOTS of motorcycles with varying degrees of riding skill levels, then that area is what your looking for.
The Parkway can be congested which cuts my fun level in 1/2.
There are plenty of other good motorcycle roads in that area with less traffic that should be visited.
Check this site for road construction on the BRP before you leave home.
http://www.nps.gov/blri/planyourvisit/roadclosures.htm
Skyline Drive has an entrance fee.
Check out this site for more information as to speed limit, traffic congestion, and the like.
http://www.exploreboonearea.com/BlueRidgeParkway/BasicsoftheParkway/tabid/312/Default.aspx
Whichever area you decide on, plan your trip well.
Motels near the Cabot Trail need to be booked before you leave or you might be shut out.
Motels/Hotels near the Dragon are equally hard to get into without prior bookings.
Have a great riding experience.