Looking for a hassle-free 3D printer

[Kelium]

The Lulzebot mini is a great option. it prints in high temp nylons and PET polymers which can actually stand up to the forces of competition, as well as printing normal prototyping plastics like pla and abs. For the slicer it users modified cura and it just work out of box.
https://www.lulzbot.com/

Another option if your willing to put down the money is the Zortrax M200, which is simply the best FDM printer on the market unless you go full industrial and buy a stsratasys model.

In terms of price/performance ratio, the Wanhao 13 is the strongest. IT is 400$ and with about an hour of set up it is the best quality printer I have ever used.
http://wanhaousa.com/products/duplicator-i3-steel-frame

https://zortrax.com/printers/zortrax-m200/