Taking a wider more cynical view it is never safe installing apps from anywhere.....
That said your best bet is to download to a thumb drive or other isolated destination drive and run anti-virus/malware scans with an up-to-date database.
Check the site's FAQ's/forums for comments, concerns, reports, etc. regarding infected apps.
Also watch for bogus sites that imitate known sites but pass along infected software.
And only download one thing at a time - multiple downloads could cause a lot of confusion with respect to what was the source and what infection may be involved.
Always keep a good backup of your system via a clone or image. Just in case.