The honest version of "does it integrate with my software." These are the systems this industry actually runs on, and what each one means for a build.
Deltek Vantagepoint / AjeraFirm management
The system of record in mid-size and larger firms, covering projects, time, billing and resource planning against fee.
BQE Core / MonographFirm management
The common alternatives in smaller practices, generally lighter and more integration-friendly.
Revit / AutoCAD / BIM 360Production
Where the work is produced. Mostly a source of files, model data and revision information rather than an integration target.
BluebeamReview and markup
Where submittal review, redlines and coordination markups actually happen, producing documents other agents can read.
Procore / Autodesk BuildConstruction administration
Where RFIs and submittals arrive during construction, on the contractor's platform rather than yours, with response clocks attached.
Document storagePrior work
SharePoint or a document system holding every drawing set, specification and report the firm has produced.
Proposal and pursuitBusiness development
RFQ and RFP responses, including the standard qualification forms that get rebuilt for every submission.