I already linked to this post yesterday, but I think it deserves some more attention. And maybe should I also add my thoughts and experience. I really like what Jackpong2 wrote. It is a good description of what I felt when I drank the best puerh I ever had. And yes, it can be applied to any kind of tea.
The subject of purity seems to be subject to misunderstandings and maybe disagreements. With '1 bud, 2 leaves', I think Jackpong2 (and his friend) mean that the leaves most be fresh and of high quality (you don't find buds around old leaves). These are also the new leaves that get the most energy from the sun and nutrients for their growth from the roots.
On the subject of 'single hill', I pretty much agree with him. Actually, as I linked above, the best puerh I had even came from a single tree! For all other teas (Longjing, Oolong, Darjeeling...) the best teas are not blends, but teas that come from a specific, often small, plantation. Despite being 'pure' such top teas have enough richness in taste and flavors to be enjoyed for what they are.
When my puerh wholesalers tell me that this or that cake is a blend of wild and plantation puerh, the first reason they have is to push costs down, not to improve the taste.
This doesn't mean that single plantation is always better than blended puerh. This is only one of the many factors entering in the making of puerh. I also had several 'single plantations' that I found disappointing, and blends I liked. But if we talk about puerh excellence, then nothing has come close to the 'single tree' puerh I had the chance to drink more than 2 years ago and no blends have come close to the 2003 Yiwu or the 2006 Lincang on my selection.