It really depends on what you want out of a card. If you're building a balance of transferrable currency and your desired transfer partner is common between Amex and Capital One (many are), then for base spend the Venture X is going to build your miles balance twice as fast.

What the Venture X offers over the Platinum card: primary rental car CDW coverage for no additional fee, small lounge enhancements (CapOne lounge(s) and Priority Pass restaurants), and it has the near universal acceptance of VISA.

Compared to the Amex Blue Business Plus from the Amex "trifecta" I think the Venture X is a more versatile base 2x earning card, especially since it doesn't have the $50k cap. You have to do a few mental gymnastics to justify the annual fee with the travel portal credit and the 10k annual mile bonus, but if you're coming from the Amex ecosystem this is a walk in the park.