TenRen is NOT a good place to get tea, although it is conveneint. I say there are online stores that sell better stuff at lower prices for consumers in the States. TenRen sells a lot of Taiwanese teas that approximate the real stuff from the mainland, but the tastes are fundamentally different, as some have already noted in this thread. I would suggest trying a lot of samplers -- the more you try, the more likely you are going to be able to appreciate it when you do get to try the good stuff. It's really the only way to really learn about tea, IMHO.
As far as Long Ching goes, I agree that Ten Ren is not the best source. However, I wouldn't discount the quality of Taiwanese oolong from the high moutainous growing regions. Taiwan's fine Tung Ting Oolong is a "real" tea...yes, different from mainland Oolongs, but superb too, IMO.
Also about Lung Ching, I learned that the more expensive Ming Chien Lung Ching are short, greenish-whitish, fat (thick), hairy, and with whole leaves and whole buds (when dry). The smell is of strong nutty flavor interlaced with floral characters. It is clean tasting, light, and smooth going down.
It IS very difficult to distinguish a top grade to the next grade, unless you are experienced. I couldn't tell why a Lung Ching I recently tried costs USD $400/lb and the next one I tried costs $300/lb.