A28 in the house, currently paired with a Yulong DA8 DAC and P18 for power. I haven't had a ton of time to spend with it yet, but based on initial reactions it pairs very well with the HE-6. It doesn't keep up with the AURALiC Taurus but maybe approaches the Violectric V200 in approximate quality with HE-6 - and keep in mind, V200 was my favorite HE-6 amp until the Taurus came along. I'll have to compare the A28, V200, and Questyle CMA800R to see which one deserves second place for HE-6.... considering the price difference, it's good company to be in.
So far I've only used balanced mode. Tried the LCD-2 and it sounded great, also an HD800 and Alpha Dogs too. I'd say this is in fact a more neutral amp than the A18, though I still don't find it thin or reedy. But definitely closer to an upgraded A100 than a downgraded A18 if that makes any sense. Fit and finish is typical Yulong (very nice).
This has tough competition in the price range. You've got Lake People G109, Firestone Bobby, and NuForce HAP-100 all priced within about $100 of each other. So far those other three all have their own specialties and none is my top choice over the rest. We'll see how Yulong does.