...if you look to the bottom of your 'My RIU' page you'll be able to read those reputation comments that jondamon was talking about, those that you have received from others and those you have written to others will both be listed there.
It is a one-stop glance at who has been around and posted a fair amount. Still not a great gauge though, but as you're around longer, you'll start realizing who the quality members are.
Also, the more rep you have, the more rep you can give.
.....and that from one with a rep beyond repute...
This fellow and others here really know their shit. The rep does reflect that ( in most cases anyway) When you ask a question, its best to see a consensus build on whatever it is you want to know. Thats how you can get the best information.