boy i wish i had a way to a/b with no lag time, its really tough to catch the subtlties between these two amps, but they are definately there...its just hard to pin down - there is a clear difference in the overall presentation of the music..
the asgard- more attack, more precision, tighter sound, and slightly more forward mids and highs, and slightly thinner sound
the ef5 - rounder, fuller sound due to more forward bass and low mids, but less prominent upper mids / highs. overall sound is a bit more laid back - voices are fuller, clearer, more true to life and pure sounding.. liquid is a good word. the ef5 definately wins the vocal presentation, but tubes will do that.
of course all of these assessments are still very early with less than an hour on the asgard.. also the fact that the ef5 is tube hybrid, and the asgard is solid state makes all the findings so far relatively on par with what is expected i suppose.
as far as overall sound quality I cant say i can make a distinction and say one sounds "better" than the other. Even comeing to a conclusion regarding which one I prefer is going to be a challenge:
lets keep in mind that the asgard was $250 and the EF5 is $400
more later.. burn burn burn..