I honestly haven't done too much. Most of what I've printed so far have been things others have made and made freely available. Usually my cousin or a friend have printed things for me. T3 parts ARE nice. Fitment has occasionally been JUUUUST a bit off but it's almost always when I have to chase some threads or because I have mismatched parts from such a broad range of dates on my stuff. That rear brace on the driver side is unfortunately gonna hit my exhaust so I have a guy that does stainless work checking out the car at some point soon and hopefully redoing some of it to correct things and get better clearances everywhere.
I think we're about at the point with 3D printers, in terms of reliability, as home inkjet printers were when I was a kid. Still not quite as mainstream but getting there. I remember inkjet printers being good for getting my homework done when I was still using floppy disks to take my work between home and school, but they were pretty slow, and the ink ran out pretty fast.
I think within the next 10 years we'll be approaching where laser jet printers are now and we'll have reliability and speed in a mainstream consumer level printer.