I'm printing this on on a more-or-less stock Anet A8. I did run into some issues which I believe are caused by the printer more than the model:
Printing the connectors "lying flat" is impossible. With and without retraction, the model is too brittle to even peel off the glass print bed. Printing them "upright" works great, though, as no retraction or travelling is necessary.
When printing with PLA from BQ, the connectors do. not. fit. Try as I might, I would need considerable force (say, a hammer) to get them into the cubes. After a bit of trying, I increased the size of the cubes by five percent (scaling them to 105% in Cura) while keeping the connectors at 100%. That way, they slide into the slots nicely without falling through, they work as expected.
I'm currently printing a few connectors using flexible TPU filament to see if that helps with unscaled cubes.
Scaling down the connectors to 95% did not work. At that size, with a .4 nozzle, the walls would get reduced to just one wall, resulting in considerably weaker connectors that break apart at the slightest pull.
I'll let you know how well the TPU connectors hold up.