They are different enough and I don't think either one is definitely "better" than the other.
Ideally you should try to listen to both and decide. Otherwise you will just get conflicting opinions from everyone here.
Do a search and you will find more than enough information to confuse you.
Those are two entirely different beasts, in my opinion. My guess is that you'll enjoy one can more than the other for certain genres of music. But, if you only listen to one type, then one might be better than the other (depending on your musical tastes).
^ yup they are definitely completely different. GS attempts to have more soundstage. Whether it does is arbitrary. I personally prefer the RS for it's more versatile sound. The GS just doesn't sound that good with rock or hip hop. The RS can do it a little better.
It depends on how much you appreciate the so-called "intimacy" factor which Grado is known for.
To me, that is the key downside for critical listening.
I just don't want to sit in the front rows in a concert every time.
For rock, maybe the first row is always better, but I don't listen to rock anyway.
The added distance from GS-1000 to me is just right, not too far like Beyerdynamic (except for T1) and not to close like RS.
It is the distance which I can either enjoy or analyze music depends on my mood.
It gives enough detail and information on recording location so you can easily tell whether you're sitting in a small recital hall or large concert hall.
It is unforgiving to lousy records, which is also important to critical listening.
For me, I don't need RS to bring intimacy, I'll just let the recording itself does the work.