I am having some major problems with the Stillwell plugins crashing my Reaper session when loading into projects with a lot of tracks. Inserting an FX (which autoloads the GUI) or clicking an existing inserted FX to bring up the GUI is often crashing my project out.
I had problems with Toneboosters plugins losing their GUI (albeit not crashing Reaper) and the developer said it was some kind of resource allocation problem with Reaper but he did manage to make some fix with his last plugin update. I am not insinuating that these plugs share the same problem but wish to alert to that issue in case it prompts a place to start looking.
The crashes usually happen when loading MajorTOM or The Rocket.