In terms of power, that's arguable. Some translations have Luffy say Cracker has the strongest Busoshoku Haki he's seen, though later translations translate it as him just saying Cracker's Haki was incredibly strong plus the former would mean something as nonsensical as Cracker > Rayleigh. Cracker has worse durability than Doflamingo seeing as how he was oneshotted by Gear 4th whilst Doflamingo took quite a few strong attacks before the King Kong Gun took him out, though Cracker has the hax to mitigate this with his biscuit soldiers. The Birdcage is more durable and strong than anything Cracker can dish out, but can't be used as a conventional attack.
They're both on a comparable level, though in an all-out fight, I'd say Cracker would win since Doflamingo wouldn't have any way to counter the biscuit soldiers and would end up being worn out after some time, unless Overheat is hot enough to burn through and strike Cracker's real body.