Here's my experience thus far with my rMBP:
Heat.) I never really notice the heat unless i'm running parallels as well or playing a game. While using multiple tabs in Chrome, powerpoint, word, and Netbeans I notice no heat increase. iStat has the fans and temps very close to normal use.
The fans.) I've yet to hear them once. Even running parallels and a game, I've never heard them (I don't run any heavy duty games, just basic ones). Again with my use (from the heat part) on a daily basis, it hasn't been a problem.
Other things.) DON'T LISTEN TO THE REVIEWS! Seriously, they are good reviews, however from the ones I've read it seems like people are trying to intentionally find issues with the rMBP. Like any product on the planet, if you look for problems, you'll eventually find them. I also think people are finding ridiculous things to complain about, such as screen brightness. I don't know a single person that uses the screen brightness at 100% all the time. I sit with a glare from my Windows on my iMac screen and it's still barely above 30% in the day. If at 100% you still can't see the screen, it seems less of a screen issue and more of a poor vision/poor environment issue. To me it seems like an iPhone 4s vs iPhone 4 (rMBP being the 4s) and how when it launched everyone said how it'd never sell because nothing is different and siri is useless blah blah blah and now everyone has one and loves it. I haven't had any issues with burn in either probably because I don't use the brightness at 100% and I actually use a screen saver (I thought that was common sense, but in another thread someone admitted they don't use one).
EDIT: Forgot to mention battery life. Screen brightness does seem to play a major factory, as well as constantly using the 1gb video card instead of HD 4000 graphics. I have mine set to only switch if necessary and if I'm not on windows as well, I can regularly see 7+ hours of usage. I've charged mine 8 times since the day it came out.
I'd highly suggest going into an Apple Store and playing around with one and compare it either to a current laptop you have (if you have one) or even to their other display computers. Play with the computer, open apps, etc. and see if you like it.
I have the 2.3/8/256 (very base model) rMBP and it is much faster than my mid 2011 iMac (That was released less than a year ago) and I couldn't be happier.
Sorry for the mini rant, I just realized how long it was lol.
With my old computer, I used to get up and get a drink when I was loading.