My usual approach with Anthem’s ARC-equipped components is to first do a traditional manual setup and to listen to the component that way, and then later to apply ARC equalization and to compare. So, the comments I’ll offer below are, for the moment, based on a few initial cursory listening sessions and without ARC engaged.

Right off the bat, I found the MRX sounded noticeably cleaner, better defined, and more muscular than many of the AVRs I’ve tried (including a number whose published specification would, at first glance, make them seem more powerful than the Anthem). This is where Anthem’s extremely conservative power ratings come into play. It’s this jump upward in observed sound quality that will either draw you to the Anthem receivers or not (meaning that, if you insist on trying to judge them purely on the basis of on-paper specifications, you’ll frankly miss what makes them desirable in the first place).
I found that, after just a very brief period of familiarization, I quickly became comfortable with Anthem’s new “simplified” remote, which—trust me on this one—is a whole lot less daunting and potentially confusing than the “full-function” remote that comes with Anthem’s Statement D2v.

I have not, as mentioned above, run the ARC setup procedures for the MRX 700 just yet, so that there may be even higher levels of sonic potential on tap. But a couple of small caveats are worth mentioning vis-à-vis the ARC system. First, relative to other auto-setup/room EQ systems such as the various flavors of Audyssey, Yamaha’s YPAO system, Pioneer’s Advanced MCACC system, etc. Anthem’s ARC setup procedures do not run from a processor built in to the component. Instead, ARC is designed to run on an outboard PC (or MAC). That requirement is not, of itself, terribly daunting, although it can be a drag to, well, drag a PC into your listening/home theater room to do the setup. But there is also one further hurdle to overcome; the ARC system requires a PC with an old-school style serial port for its connection to the MRX 700 (though Anthem advises that you can use a USB-to-serial port adapter—note, not included—provided the adapter supports two stop bits). Suddenly, ARC starts to feel like a whole lot of work… Happily, TPV owns an older PC that A) has serial ports, and B) is reserved pretty much for the sole purpose of running ARC software for Anthem components, but you may not be so fortunate.
The bottom line is that ARC is a very powerful, flexible, and effective auto-setup/room EQ system (judging by experiences I’ve had in using ARC with Anthem’s Statement D2v), but from a logistical/ease-of-use standpoint it's simply not as convenient/user-friendly as other competing room EQ systems. Caveat emptor. In the future, I hope Anthem will find a way to offer an all-USB version of ARC.
Watch for our upcoming review of the Anthem MRX 700 in The Perfect Vision.