The Cockos ReaPlugs standalones(*) have at least one problem with the Juce VST2 hosting code. When certain things are manipulated in them, such as the spectral response editor in ReaFIR, the Juce plugin hosting/AudioProcessor code will assert in debug builds. This is because the plugins call a parameter change with parameter index -1, which the Juce code considers an error worth an assert.
I did my own ugly hack in the Juce AudioProcessor code to deal with this, but I wonder if there could be some cleaner solution…Preferably these parameter -1 notifications from the plugins should cause the AudioProcessorListeners of the AudioProcessor to be notified. (For purposes of undo history, invalidating offline render caches etc…)
(*) VST2 plugins that they have released for Windows that are independent of Reaper. http://www.reaper.fm/reaplugs/