Hills -- is it true?

[Eden]

No standing on hoods or in drops -- only got "flat" bars, since this is one of those hybrid-y comfort beast bikes.

It can be more difficult to stand and pedal with a comfort style bike. I have a Marin city type bike that I've gotten back out and been using for errand running recently (its the only bike I've got that I can put a rack on and carry things easily). I have noticed that standing to pedal not only delivers less power than doing the same on my road bike, it also feels a lot less stable and I don't even have a suspension fork. I don't think that it will be impossible for you to stand and pedal - but be careful that you don't jerk your handlebars hard.
I'm guessing you bike is pretty heavy too. There is a point at which it becomes ridiculous and people will spend waaay to much money to lose an ounce or too, but when you are riding an upwards of 35 lb bike you certainly will notice the 10 - 15 lb difference that you would get out of using a road bike. You will also notice the difference in the tires - the hybrid's tires are likely much wider than a road bike's.