Dang...
I knew you were going to ask a couple of "WHY ?"
OK the 3d parts from China and most others will fail for a few reasons.
Infill not sufficient
Cheapest plastic used for the extruder or even re-used plastic used to make the plastic.
30-60% less compression strength.
There are more but those are the main reasons to avoid 3d parts.
As for GRBl to MACH it is pretty simple and more to do with power requirements and motor drivers.
You would be taking that big leap from hobby to semi pro and looking for longer term durability.
That said I probably have a few thousand hours on my hobby machine and the same on the two laser based home brew machines (printers and plywood and chewing gum approach).
Lasers can bring thier own minor issues in that FLAT OBJECTS are mostly the the things you can do until you get into 4th axis or fancy surface tracking. (can be a steep learning curve)
Yes The clock is only one of many wonderful objects I made that keep the wife gasping and allowing me to spend so much time with Arduino and my machines. It was simply a combination of open source artwork / clipart put together in a couple of hours and then machined into a chunk of red maple.
Bob.