I'm wondering what everyone's thoughts are on these drum modules. I'm looking for something with realistic drum beats and fills that are comparable to a Boss drum machine.

By realistic, do you mean how acoustic drums sound before they are processed, dampened or tuned as needed?

No. I'm not really sure what I meant by realistic. I guess not too synthetic sounding.

BFD > AD > EZD.

any of these sounds more realistic than any BOSS drummachine.
i find that EZdrummer has the most organic sound of the three due to the fact that each drum of the kit was sampled in the same room. Also comes with the best selection of MIDI beats IMO.
Addictive is great for tweakers because of its many effects and parameters. Never been a fan of BFD but i heard they came a long way since version 1 which was the last i tested.

BFD sounds the most organic and realistic since they had the least amount of sample processing BEFORE utilizing the engine's effects. EZD is by far THE most post-processed library.

BFD is the last word in AC drums. Check out those new Ken Scott SR Expansions too.

I went ahead and ordered EZ just because it's the cheapest one.

However, I did see on Sweetwater that Addictive drums is offering a free expansion pack...

Any of the listed software will be much much better sounding than the Boss drum machine.

I would also recommend Battery. It's not as "acoustic" sounding as EzDrummer but its far more flexible.

If you are looking for the sounds of a boss drum machine look here.
http://samples.kb6.de/downloads.php

Hey, I actually like my Boss drum machine. It has some decent beats and fills.

BDF is too big and complex for me.
ezdrummer does not allow me to tweak the sound enough but their electronic expansion is very good.
Addictive drum is just right not too complex but tweakable, though their electronic expansion is too small

I bought EXDrummer a few months ago and now wish I hadn't. It doesn't give you many options at all, I guess that is why it is 'EZ' but since I got it cheap on sale at Audiodeluxe, it is almost worth it for the midi files. I'm back to using iDrum for electronic sounds (you can get lots of kits for any drum sampler including Boss, I have my old DR-110 recreated and love it). http://samples.kb6.de/downloads.php

You may want to get CM as they have a version of AudioRealism drum machine for free now:

http://www.audiorealism.se/adm/adm_announcement.htm

If you're looking for AD, I'm currently selling it for 75€, including the Metal and Indie expansions, plus some single KitPieces.
Doubt you'll get it cheaper anywhere.

From my experience:
SD2.0 > AD > EZD

Haven't got BFD, so I can't comment on that.
The BFD Lite version I once had didn't convince me, that one disappeared from my system immediately.