Wow. Just wow.
I was able to get the Large Silver Box out on my own trails, with my own build for its initial shakedown ride yesterday. I kept the same tires I used on my 5" Box for comparison purposes.
This ride starts with a mellow single track rolling climb that gains about 1300' in 7-8 miles. This trail is relatively smooth, and a rigid SS bike would be my usual choice for it. I found the 6" Box to perform on this trail about like one would expect. It lumbers along at what ever speed you have the engine to push it at (for me, not too fast). I personally did not notice much difference in the performance on this part of the trail compared to my prior 5" bike. This is a good thing because I wrung my hands a bit worrying about whether going up in travel was a good idea, or whether I would be suffering on mellow climbs and hating the new bike.
I hit a little 30" side drop to transition I always hit on this trail (no matter what bike I am riding). I hardly felt the touchdown. Impressive.
Verdict, no worse. It feels more solid and put together in this sort of terrain, but still wouldn't be the first pick if these sorts of trails were all I rode

It's as good a climber as the rider, but not a good choice for a racer.
The local wild life approves of the new rims.

After an hour of mellow climbing, it is time to get into the granny. The next section of trail climbs about 1000' in three miles. It is steep, loose, and rocky with occasional switchbacks and logs. I have never, in seven years of trying gotten through it entirely clean, but have done it a couple times with only one short dab (both on the 5" Box).

This section also includes a beautiful bit of burned out forest.
I would love to say that I cleaned in no problem on the new bike, but it was a one dab sort of day. Interestingly, the dab was early on in the mellower section of climbing when I just wasn't paying attention. I cleaned all the more difficult, steeper moves in the second half of the trail. Some of this is due to MC's 20T front set up. I felt zero pedal kickback, and the suspension stayed active and plush. I never lost rear wheel traction which is amazing. The steering was no worse than the 5" bike, but definitely slack.
Again, I found no downside to this bike compared to the 5" bike. This is good.


At the top of the climb I found this second spider had gotten his dinner already. Bumper crop of spiders this year apparently.

After two hours of mostly climbing it was time to descend. I don't do this descent all that much because the top half is moto trial double track, and it is torn up, loose and rocky. It beats you to death. It descends steeply with intermdediate steep climbs, then descends steeply again. The lower half is essentially fall line, loose, rocky, eroded bumpy, bumpy, stuff. Perfect for new bike testing.

I am heading towards the flat area in the sun.
I was tired, bonked, and running out of light. If I have a technical weakness as a rider, it is loose, fast trails. They weird me out. The bike came into its own on this trail and really blew my mind. You essentially aimed it at where you wanted to go, disregarded the scree and hammered through. The level of control at speed was significantly more than my 5" bike. I was definitely impressed with the Gordo's here as I was able to plow on through the chosen line, rather than being pinged off left and right on the prior and flexier Flow build.
I don't know if this pictures comveys it, but it was stuff like this:

For miles...
This sort of stuff calls for even more travel, but that sort of bike would never be able to climb to the top, or surmount all the intermediate climbs on the descent. A 6" bike seems to be a nearly ideal compromise for "all mountain" type riding. A 6" big wheeled bike even better.
Needless to say the 6" Lunchbox exceeds expectations. I am glad I upsized. My concerns about worse ability to XC ride were unfounded. It is too much bike for many trails, but when you need it, it is really nice to have.
About the only criticism that can be leveled at this particular bike is that it is tall. 14.5" tall at the BB. For the DH racer type wanting a low slung, carving type bike, that is probably too tall. For a trail rider like myself who prefers crawling over every obstacle in their way on the climbs and slower tech descending, it seems about right.