I have some spools stocked but didn't use them yet. What I did in my last order was a 2.85mm sample and I just used it on my UM2. What I can say is that it has been really easy to set up, I just use the recommended values of Colorfabb and had very good results. Much better than with the PLA/PHA. No blobs on the outside, nice support behaviour, that means the support went off really nice and the model was very good where the support was. Here are some pictures, red is PLA/PHA, yellow nGen: The red one was actually supported with Scaffold under the spherical part and printed with the BigBox, nGen was printed with the UM2 and same material as support. The previous parts I printed of this with PLA/PHA on the UM2 looked like the ones of the BigBox...
I'm a big fan of colorFabb nGen. Extrudes at ABS temperatures, really good inter-layer bonding, lots of colors, and most importantly very little warping. This makes large objects which warp terribly in ABS printable. Plus almost no odor while printing. Solvent immunity means acetone smoothing won't work, but it seems to me that nGen takes sanding better than ABS. The downside is oozing and stringing. The nGen tends to leave super fine (like spider web thck) fibers when you move the nozzle while not extruding. In other words you'll want to tune your retraction settings to get the best results for your setup.
I did a nGen Colorfabb benchy test print today with the following settings: Nozzle temp: 230°C Bed temp: 85°C Extruded with the Titan, direct drive, at 3000 mm/min I agree with @Ephemeris : it indeed leaves fine strings (I couldn't see them with the naked eye, but here is a picture). All in all I'm happy with the result.
I've been using a lot of nGen. I like it a great deal. With most PETg's when it starts to absorb moisture it gets more embrittled. That said it's still very strong with a nice flex to it, even at worst. It's not quite as rigid as PLA and nowhere near as brittle. It has good layer bond strength as well. If you need absolute strength I'd suggest _XT, but this is a good alternative at a lower cost.