I'm drinking liu an right now. I bought it at a local Chinatown ginseng shop back in autumn 2007.
When I bought it, it tasted musty and a little rancid..."in a good way" as I said at the liu bao tasting.
Today it tastes like liu bao, shu pu'er, and liu an mixed together, but it looks nothing like a blend. It has liu bao's richness, shu pu'er's earthiness, and liu an's old hay sweetness, and a creaminess all its own. The rancid replaced by depth, thankfully. Butterscotch appears early in the brewings and is the most interesting chord. I say "chord" because butterscotch simultaneously strikes the tongue and nose: it's a fragrance and a flavor.
Before, flavor disappeared around infusion 6, and now flavor lasts until infusion 10.
A year away from the scents of the medicine shop improved this tea. You might wonder why I bought this tea at all; who drinks a rancid tea that dies at the 5th infusion, of questionable provenance (it came loose), and sold so cheap it "can't be good"?
When I tried the tea at the store, two things struck me. First, the tea coated my mouth and made me salivate, and second, my body felt a rush. The former told me this tea could mellow into something decent, and the latter told me even if it aging failed to improve the tea, I could use it to meditate and enjoy the qi. This revealed something to me about my tea habits: I'm willing to forgive almost anything in a tea as long as it takes me somewhere. I reclassify it as a "meditation tea", and I have a few of them on my shelf. I don't serve them to others because these teas' flavors would register as mediocre to most.
With so little information about this tea, and aged teas in general, what we know about tea is merely what we choose to believe. From our belief in a tea's quailty to our belief that certain signs indicate quality, occasionally approaching tea from a meta, external standpoint offers the benefit of keeping our feet on the ground, realizing that when we drink tea, we are a conduit that allows our beliefs to communicate with our realities. It's a beautiful thing.