Lets get one thing straight about Audioengines.
Audioengine A5 directly caters to PC user needs.
Whats its USP?
It gives audiophile grade sound quality - given line level stereo/mono inputs.
That means it has an inbuilt amp.
Inbuilt amp + speaker system at 20K.
With added convenience that the net system comprises of ONLY two speakers, and nothing more.
So the first point is taht:
If you wish to compare it to separate amp + speaker config - you must compare it to AMP + Speaker combo < 20K.
That means something like a low powered Norge with Polk/Wharf/Missions.
Second point to be noted is that Audioengines are marketed as Studio monitors. That means they are meant for near-field listening, and are transparent.
Most of the amp + speaker combo are not really meant to be transparent sounding. They all have their quirks and characteristics, that color the sound (some sound bright, some sound warm, some sound forward, some sound dull etc)
Third point to be noted is that most of the Audioengines will be used by PC users, wherein the soundcard river plays a HUGE role in shaping the sound.
I use a humble SB Live! 5.1 sound card with Inspire 5.1 system.
Yesterday out of the blue, I decided to remove the creative drivers, and install kxdriver. There was a dramatic improvement in the sound quality. its sounded more balanced and smooth and music, instead of loud and boomy.
So the comparison on websites will anyway be biased one way or the other.