I have the Giant Twist Freedom CS Lite 2009 model and last Friday my wife got a ladies version of the same bike but the 2010 model. These bikes are essentially the same bike as the one you have test ridden excepting, the front forks on the Twist Freedoms have suspension and a differing set of handlebars which are more adjustable making the bike a more comfortable ride at the expense however, of being slightly heavier.
I have taken my wife's Twist Freedom out for an extended ride of around 30 miles, again on hilly terrain and the bike seems to perform better than mine in terms of its 'freewheeling' ability, not drag at all and the bike feels more resonsive, but that might be because hers is a small frame size, mines medium. Her bike also features a 'Ridecontrol' computer, whereas, mine doesn't.
I'm guessing that the 2011 models are even more refined than both of our bikes, as Giant seem to move the the technology on quickly.
I have reviewed my bike in the Review section a short while ago, take a look.
I have now used it for my long 28 mile commute for a couple of months now and I am approaching 1000 miles covered, I achieved my fastest commute time last week in the sunshine- 1 hour 44 minutes!, my worst time, back in early February 2 hours 30 mins-in the driving rain and wind grrrrr! Average time, around 1 hour 50 mins.
The bike performs extremely well over the very hilly terrain I ride on, now I'm a lot fitter and lighter (lost around 8Kg in the two months) thanks to the commute, I find the battery range to be between 26-32 miles, dependent on the headwind and temperature (temperature effects the battery performance significantly).
I ride with the power assist ON most of the time using the ECO setting for around 18 miles of the journey and around 10 miles in the NORMAL setting.
In terms of hill climbing, I feel its absolutely brilliant but there again, I have not tried any other model of electric bike, I test rode mine and somehow new it was for me, comfy, quality components and after nearly 1000 miles very reliable.
I am going to update my review of the bike this weekend describing the first 1000miles.
Hope this info helps your decision making, whichever bike you buy, I'm sure you won't regret it.