Update also posted at the top:
What I have now purchased due to suggestions in this thread: 2CAudio Aether -- unfortunately, after I bought this, it will not run stably in my current Sonar project. If I start a blank project I seem to be able to run one instance stably, but multiple instances cause my current project to crash.
http://www.2caudio.com/products/aether/index.html EAReverb
After downloading the demo for this and finding the demo to operate beautifully, I purchased the full version. Unfortunately, the full version has a bug that causes it to distort the audio on my tracks (make it sound much lower). It is unusable.
http://eareckon.com/index.php?option=com_content&view=article&id=66&Itemid=74&lang=en ------------
With Spaces, Aether and EAReverb failing, I've spent $750 in the past month looking for a Reverb VST that does not crash in my current Sonar Project or have debilitating bugs. Too many times, the demo works fine but then the actual version does not (e.g. EAReverb).