I waited a while to become a mentor after I had the rank to do it. I wasn't sure if it was something I'd like or not. Now that I mentor, I will say there are good and bad times that go with it. If you have a student who isn't really interested in learning, it will not be as fun. Or if they never respond or something, then it's frustrating. When you have someone who wants to learn and has writing skills you can build on, that's when it's a great experience. You get to help someone write better reviews, which is something to be proud of.
P'Gell - I have zero patience, which is part of why I get so frustrated when people don't respond or continue to submit bad work after I've gone through and told them what to put in. I'm probably harder than most because I require lots of details and such. (Which might explain why some students seem to disappear so quickly!) I have to take breaks from it sometimes or I'll just get too frustrated. So I'll mentor as long as my patience can handle, and then not accept students for a while. I do think the reviews that get published from my students tend to be pretty good if they put the right amount of effort into it, just from me pushing with questions and wanting lots of details. So sometimes being hard on someone gives good results. I mean, I'm still nice (unless you piss me off), but I do have requirements.