Since your Element is a 29er, I would go with the Instinct BC. Why, because you could also run 27.5 plus tires if you wanted and you are used to 29s. Instinct and Altitude frames are the same design, but you do give up the Ride-9 on the BC.
My Element is an old 26er, and I absolutely love my Altitude, but if I were buying a new bike I would probably lean towards the Instinct BC. If money wasn’t an issue, I would want the new Shimano 12-speed XTR though.
I already ride a Element 970BC XTR DI2 (XC weapon) and looking for a big mountain and/or fun bike.
What will be your pick and why?
Instinct BC 90 or an Altitude Carbon 70 Sram? Same price.
I think with the Instinct BC that with the Ride9 in steepest, you could bump the fork to 170mm and run 27.5 wheels with 2.6in tires and still have an appropriate BB height and nice HTA. Rocky will tell you that the chainstays are longer on the instinct 436 vs like 426 on Altitude but I think on a 27.5 bike a more normal CS length is a good thing on a bigger bike. Heck even the Yeti SB5 trail bike has 436 CS. That Instinct converted to 27.5 might be a lot better bike going down than the Altitude actually. Has to be more stable. 4 Bikes in one (BC edition, std 140mm, Plus tire setup, 27.5 convert)
That being said, for a fun bike a Ripmo is pretty sweet too assuming you aren't hardcoring it (it can go through travel kind of quick).
I think a comparable Ibis Ripmo GX build (same as Altitude/Instinct) but DWLink and 1000$ cheaper. I have a custom 140/150mm Instinct with DPX2/Fox 36grip2/Carbon Hoops/X01 Build/Minions and I love it to death. I'd be hard pressed between it and the Ripmo tho (Ripmo wasn't out when I bought my Instinct). Especially if I was buying a complete and Ripmo was 1000K$ cheaper.