The only numbers that matter are the z layer height range (20 to 300 microns) and the minimum feature size. Z resolution is the thickness of each layer. Smaller layers usually look better, especially on curved surfaces. But the part will take longer to build.
Z resolution is the thickness of each layer. Smaller layers usually look better, especially on curved surfaces. But the part will take longer to build. Important to note that two printers with the same “on paper” z resolution can make parts that look drastically different. It’s possible for “high resolution” parts to look bad if the printer has poor X/Y repeatability (more on this in a minute).
Minimum feature size is how small a feature the printer can repeatedly make. In our case we can make a stand-alone column about 0.5mm^2 in cross-section. Due to how FFF 3D printing works (draws like a pen plotter), there are some situations where small features or features with varying thicknesses (like a wall going from 3mm thickness to 0.5mm) is not going to behave like the user expects. It’s important to check the toolpath preview in Simplify3D prior to printing to catch things like this.
What’s not captured in anyone’s specs is XY repeatability, and it’s probably the most important factor in making good looking parts.
XY repeatability works like this: I start at some point in XY space, say 100, 100. And then execute a series of random moves of the print head all around the build envelope. When I’m done, I tell it to return to 100, 100 and measure how close to the original point it is. The closer we are, the better XY repeatability we have, and the better our parts will look. Poor XY repeatability can make the layers look slightly misaligned from one another.