Before going to the specs details of the BOTM Laufender, a few notes about the build:
First about the tires, due to a mistake and tight deadlines, Igot a set of 27.5x2.8" Plus tires, but those are not the ones you really want to use if you want to go Plus. Using 3.0" tires (or even 3.25") gives you a slightly better wheel diameter and thus better handling.
On top of that, if you can already fit generous 29x2.4" tires in the XC set-up (as you can on the ONE+), going to "only" 2.8" on the Plus set-up is not that radical a difference. With the 3.0" or 3.25", you REALLY get a different animal altogether.

I know it's tempting to go 2.8" because of the weight reduction that fits this type of light frame, but the weight difference isn't that big and the ride difference is. So we recommend you stay with at least 3.0. If you want to go Plus, go Plus!
The wheelset comes from Ibis, the brand that started widening their rims couple of years ago and that I also used on some of my other bikes with great success. Even if not targeted for Plus bikes, but for Enduro bikes with wide aggresive tyres, the new Ibis 742 offer a 41mm external width with an internal 35mm size.
The Ibis wheelset is not as wide as other brands offering Plus specific rims up to 45 or 50mm, but wide enough to support a 3.0" tire, especially on a XC-Trail lightweight bike that is not going to suffer as much violent G-outs as a Enduro bike cornering on a DH at 80km/h. So far, so good, and pretty light at 1.600 grams for such a wide and strong rim. The sound of the Industry Nine hubs is magic with their 120 points of engagement, and they roll like butter...
About the fork, the new Lauf Boost model has improved one of the main complaints, which was the lateral rigidity. The new Boost model offers much more lateral stiffness than the previous one, and we think it's a good choice for an all-terrain-Plus wheels bike like this. Whereas on a 29 x 2.1 tyre, the Lauf can be unforgiving on some situations, the added contact surface and comfort that the Plus tires offer go along perfectly with the character of the Lauf fork.

Of course, it still has some limitations, especially when things get super rough on rocky downhills, but you get other advantages, like obviously a lighter bike. But also, and more important in my opinion, a feeling of "lightness" in the front of the bike, that makes you want to play more with the steering. You need to get used to it, but it works pretty well in some terrains!
Regarding the Ergon post, I am still not sure about his one after a few moths of use. On the one hand it provides a softer ride, absorbing vibrations and hits from the ground to your back. But on the other hand it also provides a bouncy feeling, that makes you go up and down if your pedalling motion is not perfectly round, which is not easily accomplished on a mountain bike in rocky terrain.
Same as for the Lauf, this seatpost doesn't have any kind of rebound control, so that movement is not easy to control. To be honest, Ergon designed this post for Road and CX use, where the hits and rocks doesn't make the seatpost move that much, and it only has to absorb vibrations and minor bumps. I think it is better suited for that, but we are always trying new things and wanted to see how it worked on a mountain bike.
Why not SRAM Eagle? Well, this is my personal bike, not a demo or tradeshow bike. I had some new 11 speed parts laying around at home, so I had to use them... Just got a new XX1 crankset and shifters and the bike was ready to go, so it made sense. If money was not a problem, I would go for Eagle, with a more extended ratio so you don't sacrifice any gear on the higher or lower part of the shifting range.
Well, I hope you like my bike, now if you'll excuse me, I have to go for one last ride in 2016!