What is the best ERP for professional services firms?

Professional services firms (consulting, marketing, IT services) have different needs than product businesses. NetSuite OpenAir, Microsoft Dynamics 365 Project Operations, and Deltek are purpose-built for services. They handle project-based billing, time and expense tracking, resource scheduling, and revenue recognition in ways that product-focused ERPs like SAP B1 and Acumatica don't do as well.