- diamondback release 3
- orbea occam M30
- scott genius (this seems more like a trail but was assured it rides like a cross country)
A few thoughts on these, just looking at specs alone. The Diamondback appears to have a leg up on the Orbea, as far as drivetrain and brakes go. If prices are equal, you're getting better components for your money with the Diamondback. But it looks like the Orbea is a carbon frame (I couldn't find an actual description though). If this is accurate, you're getting a better frame with the Orbea. With that being said, I don't know anything about Orbea frames and how durable they tend to be. You didn't mention which Genius is available, so tough to compare that one.
I agree with what others have said about the Genius being a trail bike, however, all three of these are definitely trail bikes (not just the Genius). They're all 140mm travel, with a 34mm fork and a decent amount of slack. They are very comparable as far as geometry goes.
I have ridden a Genius for the past 4 years (upgraded last year, but still own the Genius, because it's amazing and I'm attached haha). I will say it is an amazingly versatile bike. It has the necessary suspension lock outs, a half lock for more cross-country style rides and a full lock for pavement/dirt roads. I know the old models could take either 27.5 wheels or a 29 with a rear axle adjustment (not sure if this is still a feature in the newer ones). It also has a low/high chip that makes it run quite a bit different. High if you want more cross country, low for more trail/enduro style riding. I always rode mine in Low, and never had issues climbing or riding flatter, cross-country style terrain.