Yea, i never understood the misconception that the 17" isn't portable.
Yes, compared to the 13" it is heavy and big. But, it is still plenty portable enough to move around with ease.
I went from a 15" windows laptop to this, and only took on a pound in weight and maybe half an inch overall in the dimensions. I had been taking this 15" to university with me every day, walked all over campus with it, with no problems.
You wanted info about:
Real-world battery life:
Apple's benchmark is probably the best for this. Their rating is when web browsing and listening to music at half screen brightness. This is a very nice estimate, and would be close to what you would do as a writer.
The biggest hog is the brightness of the screen.
I get anywhere from 2 hours when I'm playing a game at full brightness to 15+ when I am trying to save power.
The MBP does have an advantage for saving power. You can make the screen turn off and computer go to sleep when you aren't active for a few seconds. Because it can turn back on from sleep so quickly, it really isn't any trouble.
While sleeping, the MBP uses barely any power.
This means, if your writing, you can save energy while you think of what to write. It should greatly extend your battery, and it's what I use when taking notes in University, where it's often write-listen-write-listen.
Heat:
The MBP does get hot. Any version of it does. The heat from the circuit board simply has an easier time transfering into metal than it would if this was a plastic case. Notably it gets hot by the ports on the right and at the top near the display.
I've noticed it can be hot to sit on your lap if your doing certain tasks, or if its hot outside.
Personally I don't mind, the keyboard doesn't get hot, so it doesn't effect me.
Even playing very taxing games, only the top gets to the point where it might burn you, if you left your arm there long enough.
More impressive is how fast it cools down, and one of the advantages to the mac. Try doing something stressful, and then going back to just a browser or the desktop. It really takes no time at all to cool off.
Fan Noise:
I have an SSD, and the MBP has been silent except while gaming. Particularly taxing games will make the fan go.
Not really a big deal, and when doing other work (even hard work like Photoshop), I don't hear any fans.
Screen Quality & Backlighting:
I really like the screen. the 17" has very small text, because of its high resolution. But the text is very crisp, making it easy to read, given time to adjust a bit.
The color and backlighting are both nice, though it is possible to get different screens, some from LG, some from Phillips I believe.
As for anti-glare versus glossy, thats up to you in the store. I need color accuracy, and found the glossy did better for my uses.
Is it a great machine?:
Yes indeed.