RR is more critical and has higher standards. The writing is also by far, on average, much better. People here can't handle the stricter standards and therefore tend to fall back on the classic "but trollz tho" and I've gotten to where I ignore these people. This thread alone is amusing.
@Discount_Blade tends to have some amusing opinions about people who shout troll at the drop of a hat. Apparently, according to him, this forum used to be plagued with people making threads to cry about trolls the very second they got a 1-star.
Also, seeing as people drop 5's on stories that I very much doubt they deserved, I think people have very little right to lose their marbles over a 1 star. I mean...so much of the literature on this site is ranked at 4.5 and higher, and it's just...not deserving of that high rank. I mean stuff with obvious misspellings and grammar flaws in just the synopsis still have a 4.7!!! I mean seriously!!? Let's not even talk about the actual story content.....
Which is why, I like SH, but I like RR just as much because when you get a good rating on RR, you probably actually earned it and not because your popular and socialize frequently in the forums, which is something so many other writing sites fall victim too.
But still, SH is much more forgiving and kinder in its ratings. So if you don't want harsh criticism, or at least not as much of it, than here is your best bet.