I've had my Audioengine A5+ speakers for almost a year now, and really liked them a lot. I never thought of them to be lacking.
Recently, just for fun with full intentions of returning them, I went and picked up a pair of Adam A7X monitors. Stupid idea... My Audioengine A5+s are lacking in my eyes (well, ears) now. The Adams basically took seat on my desk and said "let me show you what you've been missing, amateur" and blew me away. And these Adams are brand new, not even broken in yet.
The Adams remind me of my HD800 headphones - I had no idea that speakers/monitors were capable of this kind of accuracy and "soundstage effect." Drums that are meant to be in the background really "feel" like they're in the background - on the Audioengines, I would just "hear" them as if they were meant to be in the background. Not to mention I'm hearing things on my Adams that I've not even heard through my HD800s before.
Granted, the Adams are $600 a monitor... but they are seriously just begging to stay on my desk and not go back to the store.