I brought in some E3D Edge filament to test. It's a CPE which means low warping, like PLA, but higher stringing than PLA.
I replaced the nozzle with an E3D V6 nozzle. This has a 7 mm hex versus a 10 mm hex for the Makerbot-style nozzle that was previously on the machine. I recalibrated the Z offset and leveled the bed.
I had a genuine problem loading material. There is a flat somewhere in the feeder. I suspect it's the tube coupling used to secure the bowden, or the tube itself. Ultimaker puts a conical chamfer on the inside diameter of their bowden tubes to help with this.
So to load material I had to spin the whole machine around and fiddle with the feeder. I ended up having to sharpen the filament like a tent stake. When I went to spin the machine back around the part of the feeder that sticks out considerably to the left of the printer caught on the pallet rack and busted off. It seemed to be a vestigial portion of it, though.
In whole I found the feeder to be pretty ridiculous. fbrc8 does not list the Ultimaker 2+ feeder on their website. I can call and see what it'd cost. I also have an E3D Titan I can donate. The bowden coupler for it is $7. E3D has very good documentation for it and we can supplement on the wiki. It's not a perfect solution, but I feel it'd be in the right direction.
The menus on the control panel did not look familiar to me. If we're going to keep a custom firmware like this we should document that menu system. A tree chart would probably be sufficient.
Speaking of the firmware, it allows the user to set the hot end temperature up to 300 C. That's probably too high for the hardware. I think 260 C is stock.
While leveling the build plate I found the filament path in the head to be very flimsy. The fan shroud is melted and barely hanging on. A metal fan shroud is $36. A metal isolator spacer is $5.
The bowden tube is too short. When the head is all the way forward it is putting a bending moment on the bowden coupler on top of the head. This wears the bowden tube and coupler more quickly than necessary. While this bowden setup is respectable, I think it's a bit too much. I couldn't get the tube out of the feeder to see if it was chamfered, as it fit in the coupling very tightly. If I used tools to remove it I'd likely damage it. Part of the bowden tube's job is to be serviceable, so it fitting this way hampers that to some degree. Considering we've had a bowden failure recently, I don't know that this kind of tube setup is really better than the regular setup from Ultimaker, or a replacement tube from Capricorn.
I consider the bowden tube, coupler collets, and coupler collet retaining clips to be wear items. All of them together are $23.
So how did it print? Very, very stringy, even for CPE. But otherwise very very good! The keel line is one of the best I've seen! I've removed the print and set it on top of the printer for others to inspect.
For just under $100 I can correct the above and get it fully documented in the wiki.