Yes I know these aren't GW minis, nor are they mine... I had a work colleague who got some models 3D printed online at Heroforge for a Shadowrun campaign he and some friends were playing. He brought the models in to show me and I offered to give them a lick of paint, because I am a nice guy!
As you can see the models had a lot of issue with striation - this due to the choice of using the cheapest print option (not going to pay more until you test the quality!). This also made them a bit of an arse to paint as they sucked a lot of paint up. I did give them a pre-coat of watered down PVA to take away the worst of it - the key bit was that the models got paint on them, not that they needed to be painted to award quality. The photo quality is also not the best (sorry!)...
As for Heroforge, it's a great website (IMO) particularly if you are into creating a unique character for your games. In fact, you could waste HOURS tweaking around with your individual design, so be warned. Also I'd suggest paying the higher price for the premium plastic though if you are intending to do any more than give them a spray of black paint.
How on target am I?
Weeks of the year complete: 13
Models painted: 16
Vehicles painted: 1