I found the I get better Z results by cranking up the voltage on the driver a bit. The downside is that it runs very hot. I added a fan to the control board to keep it cool. The only other time I worried about my stepper motors is with my modified extruder. I went with am Itty Bitty belted design and found the motor got quite hot. I ended up redesigning the gears to gain some mechanical advantage and not the motor hovers around 40 degrees. The fan shroud can be found here from thingiverse.

As far as slicers, I started with slicer but could never get the results I was after. I love how many options you have control over however. The mid print performance seemed to be messy and not done well. The movements are very efficient. I just couldn't get the extrusion to look the way I want. I have found that I get very good top layer performance from it...but it took a lot of tweaking. I have to tweak a lot per roll to get it acceptable.

I have been using Mattercontrol and I really like it. I get awesome prints time and time again vs. Slic3r. The top layer isn't as tweak able but it is acceptable. What I like is that I can just enter the specific diameter of the filament I am using and I get an awesome print. I highly recommend it.

I want to try simplify3d but can't get myself to pay for it. I'd really like a demo but they do not offer one. I haven't found a direct comparison between Mattercontrol and simplify3d yet.