WA7 is a very good amp with a lot of headphones, but I can't say it excels with any.
I used it for a year with HD800, went through all the possible tube combinations and... sold it.
HDVD800 is tailor made for the HD800 and is close to perfect for them, but to get the most of it you need balanced connection. If HD800 is your only headphone (and you intend to keep it that way for a while), then it would be within top 5 solid state amps. But with high output impedance it may not be so good with low impedance headphones.
Both of them have DACs that aren't proper matches for the amps, so in case of HDVD800 you may be better off buying the HDVA600 instead (which is the same amp) and get a better DAC. With the WA7 you don't have a choice, but I don't think it's DAC adds as much to the price.