I was looking for some nice powered speakers for my music room. I also wanted a better quality dac than what was available on my laptop so having the USB connection was a key. I was looking at the Audioengine A2+ at first because I didn't think I needed the Bluetooth connection option. But I am glad I got the HD3 instead as I've found myself using the Bluetooth connection the most and the range is impressive; the speakers are in the basement and I could connect easily from upstairs. I also like the look of a grill for the speakers. The only odd thing was having the Bluetooth antenna sticking out so much but I could orientate it sideways to sort of "hide" it without any loss in reception.
Setup was super easy. I was contemplating needing to add a subwoofer in the future but discovered the bass response is more than adequate; these are nothing like some speakers that have a pronounced bass boost. I would describe these as fairly flat. I especially like them for acoustic music and vocals.
Audioengine also has an excellent website and customer service. I e-mailed them with a question and they responded within 24 hours.