I use Acourate. Been using it for 2 years. Initially I only used it for room correction. Eventually implemented active crossovers (within Acourate) between subwoofers and the 3-way speakers, then added a pair of monoblocks and added another active crossover on the woofers of the 3-way speaker. So now I have a 3-way active system with tweeter and midrange being in one channel and keeping the passive xo. Next up is time aligning the channels. Acourate is very powerful. Very powerful, but involved. There is no going back, though :-)
Before jumping into Acourate I compared it to Dirac. In comparison, Dirac is not as powerful, it's a lot more expensive if you want to go multi-way, but it's a lot simpler to implement. It is simpler because you have less freedom to customize to various system settings.
Working on room acoustics is wise. The less you need to correct digitally, the better.
Before adopting Acourate I was using REW, with a measurement mic and outboard soundcard. Please note USB mics, and outboard USB soundcards like mine, have a ADC built in. This is OK initially...but it now has become an issue for me as the internal clock differs from the DAC internal clock and that becomes an issue when you want to time-align drivers accurately.
Two years ago I was worried about digital processing. But I ended up trading my Lamm pre and purist 2-channel DAC and USB-to-SPDIF converter for a Lynx Hilo working as 6-channel DAC and using the digital volume control from JRiver. My system sounds better now. I actually still hold the Lamm but that's more related to my affection - I know it will not make it back into the system.
For those interested in learning about Acourate, these are what inspired me:
http://www.computeraudiophile.com/content/529-acourate-digital-room-and-loudspeaker-correction-softw...
http://www.computeraudiophile.com/content/556-advanced-acourate-digital-xo-time-alignment-driver-lin...
Cheers!
