Not much to report back as yet.
I'm drinking some of their Dragonwell right now, actually. I've sampled a few (at length) from different sources - nothing on the order of what one might get from Red Circle Tea, but I'll say that the Long Jing from David's is very decent. The leaves are large and beautifully shaped, no sticks or stems. The aroma is, to me, classic LJ, and particularly sweet. There's a certain toffee-like sweetness to it, especially as one gets to the bottom of the cup.
It stands up to very high temperatures, no bitterness. It doesn't go flat or tasteless even toward the fourth or fifth infusion. It's more sweet and somewhat chestnutty rather than strong and vegetal. The aroma really mingles well with the flavour. So there's some character there throughout.
I find that at some point during the course of several infusions LJ will turn somewhat astringent. Not necessarily in a bad way, but it will become evident, and might even emerge as a dominant element. Not really the case with David's LJ. Even with longer infusions and higher temperatures, the astringency is just in the doorway, but never really makes it through. The sweetness and light chestnut tones remain at the fore.
I think David's Tea's Dragonwell has good things to offer. It's worth a try.
My preferred brewing method for LJ in general is with a gaiwan (one of the gorgeous, super thin-walled, pure white ones from The Tea Gallery), using water just off boiling that has been allowed to cool for about 30 seconds, pouring against the wall of the gaiwan rather than directly into or onto the leaves. This method is especially nice for the first infusion. The leaves will float on top in a semi-wet state, making for a marvellous olfactory experience.