Anyone Worked With Construction Estimating Consultants Before?

I’ve been looking into ways to make project planning more accurate, and I keep hearing about construction estimating consultants. I’m curious has anyone here has used them for detailed cost planning or material breakdowns?

Do they really provide better clarity compared to standard estimating software? And how much do they help with avoiding budget surprises during a project? I’d love to know what kind of experience others have had positive or negative before I consider bringing one on board.