I don't think it's true to say that it "only works on a fraction of the exist machines". I've tested over 20 C64's and all of them apart from one was VSP safe, so only one failed the test. Also I'm not seeing much feedback from user's saying that this port is crashing on their machines.
Also all of the C64 emulators are VSP safe as well as the C64 Re-Loaded 1&2, Ultimate 64 and TC64 - all VSP safe. It's such an obscure problem that an emulator would have to build it in rather than it happen by default.