The most time consuming part was waiting for applications of contact cement to dry before pressing pieces together. They aren't designed to interlock but they were pretty easy to align. The contact cement gives you a second after you press them together to adjust slightly. I could see if your printer isn't the best or optimally configured it might be difficult. The mating surfaces have to be extremely accurate. Resin applied with a roller is all that's needed to smooth the surface. The lines inherent in 3D prints disappear.
Toby, MDF is definitely a great choice if you have access to a capable machine. For us that would have required outsourcing the cutting work or a huge investment in money and space to build and store our own machine. CNC milling is a great fabrication process but 3D printing has a lot of value and versatility in our opinion.