Where do you live/ride? The Delano Peak has a much more “modern” geometry – slacker head tube, steeper seat tube, longer reach, etc. If you are riding steep terrain, this will make things easier. How much? You probably wouldn’t have an issue on the DB either, but that is a 27.5 frame from a few years ago (was modern then) that they recycled into this 29er version. Not bad by any means, but it isn’t the latest and greatest.
I’ve only heard good things about the XFusion Manic dropper on the Delano – super smooth, easy and cheap to service. The KS on the DB is going to be more expensive to service.
Shimano doesn’t make a bad brake IMHO, so you aren’t “downgrading” with the Delano even though they are only SLX level. My M8000 brakes (same as the DB) have the typical “wandering bite point” that many Shimano brakes have if they don’t have a perfect bleed, which can be terrifying at times. That may or may not be better with the newer generation SLX models.
DVO suspension on the Delano is top-notch, but local service might be an issue (I’m running into this right now with my XFusion forks, who only has 1 legit service center in the US). More places can do DVO, but it’s not as common as Fox. Many local bike shops can deal with Fox suspension in-house.
The double upshifting on Shimano is great, as is the pull to upshift option, but you can thumb that button pretty quickly on SRAM as well.
Have you looked into the new Giant Trance X 29? Cheaper than those and pretty solid components as well. If I lived in a mountainous area, that would be at the top of my list.