The low rate.
Well, really, it's the grinding. While SHRs are WAY too easy, Low Rates are the dynamic opposite. I don't really have the time to grind and grind and grind and feel like I have absolutely nothing to show for it. Heck, I already have to take Very Long Breaks from leveling on the High Rate server I'm on, because I absolutely, positively HATE Bio3. How does anyone on a Low Rate even survive in there? I have problems with a level 300+ Sinx...
But I digress. It's the grinding. Elitism can be found anywhere. Having a great, nice community might offset a bit of the dislike for the abysmal rate, but like I said before, I just don't have the time to grind. RL gets in the way, and I kind of like it like that.