Had a few hours to digest the new sound and do some initial tweaking. Here are my thoughts.
The Emotiva XPA-3 is big, brute, and awesome. Setup was easy, no guesswork and no surprises. Just make sure you have a strong back to manuever it around because it is very heavy (50+ pounds). The 1.7's LOVE power. I'd heard bits here and there about hearing details in music and movies that you'd never heard before when these types of speakers have enough gusto which I'd previously dismissed as fanboi rhetoric. Not true. I want to clarify this for the curious who may be reading and skeptical like I was...this effect is a combination of power and fidelity. In music you will pick up on an instrument or a sound that you'd never heard before because with the extra power it will be amplified enough to be distinguished from the foreground music. That, on top of the room filling effects of the Magneplanar speaker design bring a depth to the sound that just has to be heard to be understood. On that note, I want to give an observation that may or may not hold true for you but worked out great for me and my particular taste. Per advice from my dealer, I had the tweeters facing inward prior to installing the XPA-3 and while they sounded good, I could tell the imaging wasn't quite right. I played with the toe and the distances from my seating position, both of which helped, but never quite cured the problem. The best way I could describe it is it felt like the sound was playing in my direction, but aiming for something behind me...very very directional. The sweet spot was there, but felt lost. Of course, as soon as I installed the XPA-3 this problem was that much more pronounced. I swapped the pair and placed the tweeters facing outwards and BOOM, left and right channels disappeared into the center right where it was supposed to be. YMMV, but I thought it was worth noting.
What was most impressive to me was what the XPA-3 did for my center channel. Last night I watched a football game which, like most TV, is center channel driven. In sports, 75% of the sound you hear is the commentators talking during the game which all comes through the center channel. This is hard to communicate (or probably believe if you've never heard these speakers yourself), but with the new power I can tell that the commentators are in a box speaking directly into a microphone, rather than just voices coming from the center of my TV. You can tell that there is noise cancellation effects going on from the broadcast end. You can tell that the commentators voices are running through sound enhancement equipment, like what you hear on the radio. You can tell that the room they're in is somewhat noise proof, but when the crowd roars its not coming from the L&R channel like when a play is being run and its muxed in to the audio stream, but rather that what you're hearing is also leaking from the stands, through their room and into their mics and into your center channel. The MMGC painted this auditory picture of what was going on so well that it just immerses you into the experience. I was very, very impressed.
I haven't EQ'd my system or played with any crossover settings yet so I know the sound will only get better. First order of business will be to blend in my sub with the 1.7's to get more blended bass. As it stands right now, the 1.7's play so much of the low end so well that I forget sometimes whether the sub is on or off. But when I play something bass heavy, the rolloff is very abrupt and I can tell there are some gaps that need adjusting. I plan on bringing the sub up a little to around 80hz and crossing the 1.7's a little higher to save them from those "above normal volume sessions" I tend to find myself in. Oh and a note about volume: the Maggies can be very deceptive in communicating just how loud they are playing. With normal cone speakers, the perception of the noise floor tends to float around either distortion, stress on certain frequencies, or both. With sound coming in so clear from these speakers, you have to physically readjust your definiton of "loud". There is a limit of course, but with the XPA-3, it is much much higher than when I was attempting to run the 1.7's straight from my Integra AVR. To give you an idea, I cranked up a song up to 2.0db on the Integra and I couldn't hear myself talking to well, myself.
So all in all, the investments I have made have paid off and I am very happy with the 1.7's. If you're thinking about purchasing these, ensure you have enough power behind them and you will not be disappointed. I think a XPA-2 on them would be PERFECT, but that depends on your room dimensions + desired volume level. I would like a tad more headroom than I have now, but I'll save that for next years upgrades.