RV seems to be the most used in shops I go to. I tried buying it once but never got a response - wish they just had a store instead of email only. I heard you need to open a support ticket to get a response on anything from Autodesk.
I've also used DJV and MR viewer: https://mrviewer.sourceforge.io/ Both are a step up from VLC and have a lot of the features of RV but they don't perform as well for caching frames. I lean towards MR Viewer usually but it's only available on Windows and Linux.
Also there is BView, https://bufsoftware.com/https://bufsoftware.com/products/bview/. I like this one as well. It's made by Buf and is fairly fast for the job. Available for Mac and Linux.