I've been an EZD (and Superior) user for many years.  When I decided on EZD it was a no-brainer.  I won a copy in a give-away!  I had been looking at AD and loved the sound I could get from the kick and toms in that program, but free is free and I never looked back...buying up 90% of the expansion packs and extra MIDI packs and moving into Superior and buying those expansion packs as well.  I LOVE Toontrack's ease of use and functionality.  they seem "intuitive."
 
now that Sonar has included AD (1) into X3, I decided to use it in a project.  I like the GUI, I like the different kit pieces I can choose, I like the sound of it...but I HATE the way it sends kit pieces to multiple outputs.  there is no control over the way it chooses to output separate tracks. it doesn't have enough outputs for each kit piece to go to separate tracks, so it groups some of them and decides that on its own how to group them.  and I have to "figure out" where each kit piece went, there's no easy way to tell like there is in EZD/Superior. 
 
In EZD, I can choose the mono or stereo track numbers listed right there in the Toontrack GUI!  I can group them myself if I want, or I can send each kit piece to its own track (for the most part, that doesn't occur in stuff like Latin Percussion or whatever that Urban one is because there are too many pieces to the kit).
 
a LOT of people love AD - so tell me why you love AD and if you've tried both programs, especially tell me why you like one over the other.

Reece,
 
We are working on collabs together, so I know you and I have already kind of conversed about this to some degree, but I thought I would continue with some of my thoughts here.  I look forward to some of the answers that will get posted.  I was on AD1 also when we first talked about this comparision.  I have since bought the Fairfax bundle and upgraded to AD2, but I really have not had a chance to really test the waters with the upgrades much. 
 
I too, was dissappointed with AD1 and how to assign kit peices to individual tracks.  The biggest downer for me, was control over the cymbals, ride and hat.  I have always really liked the tone of the kit peices in AD1 and the new tones in AD2 seem even better.  In particular, both of the Fairfax's sound outstanding. I have always thought the cymbals were lacking a little something in AD....not enough ring....like they decay to quickly.  Granted, I have not tried to go into all of the FX's in AD and adjust them to make the cymbals ring longer, so I could be missing the boat on this. 
 
I like the way EZD2's midi files are laid out for the songwriter, very easy to find what you are looking for.  I love the way the Fills are broken into 1/4, 1/2, Full, and easy to find the right length fill for the job.  In AD, the fills all seem really long and I usually have to go in and find a small portion to trim into a Fill that doesn't feel overplayed.  I like the way you can now tap out the beat in EZD2 and it suggests patterns for you...that is really slick.  I like the cymbal sounds better in Toontrack, but some of the kit peices seem a little whimpy some times. 
 
Just last weekend, Clint Martin sent me a copy of the EZD map for AD2 and I gave that a quick whirl....seemed to work perfectly.  This may be my solution for the best of both worlds.  I tried building a short track in EZD2, then I dropped that midi into AD2 with the EZD map inserted into AD.  Worked perfectly!  Now if I could just get the cymbals to ring a little nicer in AD2, I think I would have a combination, best of both worlds going. 
 
To be fair, both EZD2 and AD2, now seem to have way more control over the kit tones and FX applied to them.  I have not had the time to really push either programs to their limits.  The Fairfax's are awesome though, especially the drier drum sounds.   

I think maybe whichever you happen to fall in love first sets the standard. Unless it completely surpasses it, any similar piece of gear usually end up feeling quirky because it does what you expect but in ways that feel counter-intuitive.
 
I do have AD but I haven't even installed it on my new studio computer. Not that it isn't good, but  I'm just so used to EZ and SD that I didn't see the point.
 
OTOH, even when properly remapped, there's something about the Toontrack midi grooves that just doesn't sound right to my ears when played back using another drums plug-in. Could have something to do with the way EZ and SD handle velocities. Which sort of negates their purpose for me.
 
AD and BFD Eco seem to "translate" correctly.
 
At this point though, I'm not even using EZ or SD anymore. Logic Drummer is the way of the future, I tell you. :P

I really like AD2 and it responds nicely with my pads.  However, I own SD2 and now EZD2 and with both of those programs, I have plenty covered.  The midi libraries, the add-on drum packs, the song writer features in EZ2 and the power of SD2 make a total system for me.
I am waiting for SD3 and hope that will consolidate everything into one program.  

I have both EZD2 and AD2. I started with EZD, because it was the thing to have for drums. Lately, I find myself working with AD2 more often. The tweakability helps a lot when trying to get a kit sounding just right.

Reading opinions of AD (1) makes me think I should revisit it, but every time I have tried it I have been disappointed, it seems to be on a par with the EZ1 factory kit with some effects.
 
I upgraded to EZ2 but have not used it much. I still tend to use my EZX in Superior.
 
Superior remains my go to, some of that is laziness as I also have BFD3 which is probably the best out there. I need to set up my track templates for BFD 3 so its easy to drop into a project. The cymbals in BFD3 are a step above and the add on Zildjian pack is great.
 
I have several Superior Drummer templates with busses and effects (T-Racks and pro-channel) set up so I can get quickly to the sound I am looking for.

But the deal killer for me on AD is the way it handles multiple outputs.  I can't stand not having full control over where the kit pieces are assigned, especially when it assigns multiple kit pieces to a single track.
 
in EZD/Superiror that's not the case.  if there are more kit pieces than there are output tracks, you stiil have full control over which outputs to team up.