Printing more slowly, especially the first layer, can allow some improvements in quality. I printed this part for someone at the office, and you can see how it is made in more detail. Perhaps interesting for this that have not looked closely at 3D printing before.
The holes are 1.5mm diameter.
Some high resolution images...
[printed using ColorFabb nGen on a Lulzbot TAZ 6 with 0.5mm hot end at 200µm layers]