It always could 'deal with it', the issue is getting it to render identically to PowerPoint, which is virtually impossible to accomplish for non-trivial presentations, it seems. Likewise for other Office files. iWork has the same problem.
But surely Google docs presentations are fairly non-repeatable across browsers, operating systems, and years.
All "modern" browsers render Docs well. Not sure what difference the OS makes, after all, it's just a vessel for the browser's rendering engine.
Font rendering can differ between different OSes but it's usually not too bad.