Yah, printed extruders are pretty much the norm. With the exception of the Printrbot extruder, and the Micron3D, there's a surprising lack of good open-source metal extruders. Maybe that's a justification to get a CNC mill haha!

I hadn't realized how popular the rail mod was for the Taz. A lot of the press and reviews I've seen have been on a stock Taz. I know the old Taz4 had issues with the hot end and PLA, but that was fixed with the Hexagon on the Taz 5. I wonder if it's truly an issue, or makers just looking for ways to upgrade their machines!