Well the demo/final thing for me is more about the quality and depth of the sampling, rather than the complexity of what's going to be triggering those samples. Whether it's simple rock beats or crazy technical and intricate stuff, lower quality drum samples tend to stand out. More so with the more technical stuff, but you can still here it in simple beats too. Dodgy cymbals can can really stand out, but the drums also, especially when you're doing fills 'n' shit. Part of it is also the sequencing though. I dunno what the new EZD is going to sound like, but the original one for me always sounded a bit artificial to me.
There are I guess a few ways you could go about putting the drum tracks together. The easiest ways I guess would be just piecing bits together from MIDI sample packs, or just playing the parts on an e-kit if you're competent enough on drums. The latter could of course be rather expensive if you don't already have an e-kit, so we'll just ignore that. I dunno what the go is with SSD stuff, but I know Toontrack have an arseload of MIDI packs available, full of all kinds of different beats and fills in various styles. I'm guessing SSD has similar stuff available, if only so Toontrack don't have that over them. That said, I've never really been into that way of doing things. I generally have a pretty good idea of what I want the drums to do, and it's quicker for me to just whack it all down with the mouse rather than search through a huge library of sequences to try find something that's close to what I want, which I then have to finish off with editing anyway. That said, the TT stuff I know are sequences recorded from an e-kit, so there's already that "real drummer" aspect in there, without having to dick about with all the trickery of programming in some "human error" or whatever. And if you just want fairly straight forward rock beats 'n' shit, I'm sure TT's stuff or whoever else that does 'em could easily cover it.
Another way would be whackin' the notes in over a few passes using pads or a MIDI keyboard (or pads on a MIDI keyboard). Some people like doing this... I tried it years ago and didn't like it personally. I'd be doing passes over and over, and then I'd end up quantizing it anyway coz I can't drum on a fuckin' keyboard, and then go use the mouse to program in the "real drummer" aspect. So in the end it took me way longer to stuff and annoyed the fuck out of me in the process. But I've been sequencing music in MIDI for 15 years or something. If I'd started out hitting notes on a keyboard, by now I'd probably think clicking them in one note at a time was a retarded way of doing it.

So yeah, I just click stuff in directly with the mouse in the Cubase drum editor. Do Soanar or Reaper have drum editor screens? It makes it a lot easier than working on a piano roll or standard notation. Again, talking about Toontrack coz that's what I know, but a reasonable sized kit contains a shitload of different notes. The hats might have 3-5 levels of openness, maybe a couple for closed (one tighter than that other), the pedal, maybe stick tip, etc. The snare might have a normal hit, a sidestick, a rimshot, a muted snare, etc. Sure you can just do away with a lot of this stuff, but if you want to put together a really good sounding track for a final recording, I imagine you'd want the kit available to you in as much detail as you could get. So yeah, trying to keep track of all that shit on a piano roll or in standard notation? Bit of a bitch. If you have a drum map screen, or something like it where you can name all the notes rather than having to remember what a C#3 is or whatever, that definitely helps. Even if most of what you're doing is just pasting in pre-made beats, it'll still help to have a screen that actually makes sense to look at.
I also don't particularly like "auto-humanise" type functions. Complete mistakes aside, the variations in timing for a real drummer (compared to dead-on snapped to grid) aren't necessarily just completely random fluctuations. Aside from deliberately playing behind the beat or whatever, the variations are related to how a drummer moves. What it means though is that I end up shifting every single note around and adjusting its velocity individually, which takes an absolute fuckload of time. I quite enjoy programming drums, but that shit drives even me batshit crazy.
So yeah, if copying in pre-made beats from a MIDI pack covers what you want, do that.
