What is the recommended tool for viewing Visio files on a Mac?

A free reader would be the best solution, but if there is a decent editing package for structured diagrams, then I am willing to cough up some money...

Edit: I'm currently downloading LibreOffice, which is supposed to be able to open and edit Visio documents. I've heard OmniGraffle can as well, but the reports I've read suggest that it has a habit of randomly replacing objects or moving them around, not really very helpful when opening technical structured diagrams...

Tried https://www.lucidchart.com/pages/visio/visio-viewer-mac ? It's a bit strange as it's all web based, but worth a go maybe.

Thanks, I'll have a look.

LibreOffice did better than I expected, the process boxes were more or less in the correct places and at least the lines betwene objects were going to the correct objects; a huge improvement over OpenOffice from a couple of years ago. But accurate representation is something else.

I can use it to refer to diagrams as I am writing documentation about them, but for using the diagrams in other applications or editing them, it isn't good enough.

A big problem seems to be lines. Lines that are set as ---- Yes ----> appears as -------------> with the Yes in the middle of the line as if the font was formatted with "Strikethrough"...