Yes, both Gliffy and Miro offer a Free Trial.
Gliffy is designed for Large Enterprises, Medium Business and Small Business.
Miro is designed for Large Enterprises, Medium Business and Small Business.
Pricing for Gliffy Starts at $8/Month when Billed Yearly whereas for Miro Starts at $8/User/Month when Billed Yearly.
Some top alternatives to Gliffy includes Miro, FigJam, SmartDraw, Cacoo, Microsoft Visio, DrakonHub, Creately, Lucidchart, EDraw Max, DrawSQL, Quick Diagram and diagrams.net.
Some top alternatives to Miro includes Collaboard, Microsoft Whiteboard, WhiteboardFox, Conceptboard, MURAL, Lucidspark, Whimsical, Board, Zoom Whiteboard and Witeboard.