I haven't heard those two specifically but I have a *really* hard time believing a cheap opamp-based amp like the Atom has anywhere near the sonic performance as the Asgard. Been there done that with opamps. Sterile, flat, measures great I'm sure, and probably comes with a cheap SMPS.
The Emotiva is a different animal. Looks like Class A/B amp with a headphone output section added. So good amount of power. But Emotiva's business model is basically take run of the mill Class A/B designs and repackage them in nice, affordable, decent built units. IOW, you get a little bit more than what you paid for.
Both companies also cater more to the 'it all sounds the same once level-matched' crowd. So different priorities.
IMO once you hear good Class A-biased gear, whether tubes or fets, it's really hard to go back. There are always exceptions of course (Neurochrome?).
Put another way - I have the Cavalli Liquid Spark, which is FUN. Man, I love that thing. So cute and sounds so good. It also costs $110. The Asgard is only $90 more. The Asgard 3 kills it with fire, stomps on it, grinds it bones, and eats the ashes. It should not cost $199. I've been in the hobby long enough to recognize that right away, even if it's not quite my preference sonically.