I felt the asgard was pretty boring with the he-500. It does a good job and I could enjoy the music but I didn't feel as if there was much to it. I read the same review which made me think it would be a great buy.
Vioelectric v100 / v200 is very well regarded with the he-500 so I think that is worth looking into. I think the v100 with a DAC built in is about $1k, while the v200 is around $1200 w/ 24 bit dac. I recall a very respectable forum member saying the v200 was the best solid state he had heard with the he-500.