The main issue here, in my experience is memory consumption. SketchUp is limited to 4gb of ram, it doesn't matter what hardware you have, what operating system you have, etc. That's why Maxwell has an issue, and it's why V-Ray has an issue. If you are hitting that memory limit, you're going to crash. Sketchup on OSX appears to consume more memory than it does on Windows, as does the V-Ray plugin. Also, if you have multiple Sketchup models open on OSX at the same time, each model contributes to that 4gb memory limit. On windows, this is not the case. Each Sketchup window has it's own 4gb playground to work with.
Many other modeling applications have made the jump to become a 64bit application, which allows an application to use far more memory. Currently it's not even possible to have a computer that exceeds the maximum amount of memory that a 64bit application can use (it's something like 18 exobytes).
When you load SketchUp, it loads any extensions that are currently installed and active. If you have many plugins, you're going to use more memory. Just loading V-Ray's dependencies can take some time, and eat up quite a bit of memory. V-Ray does indeed scan over the model and look for textures, materials, lights, proxies, etc. During that process, it consumes more memory as it builds various data structures that help us interact with the SketchUp model, and even render it in real time.
It's possible to have a model that will crash due to memory consumption on OSX, by simply opening the model, and due to OSX's feature which will allow an application to reopen whatever documents were last open in the application, it's possible to end up in the crashing loop as described above. The workaround of moving a file is very effective in breaking the endless loop of crashes. This prevents V-Ray from scanning the file, and prevents SketchUp from loading the file in to memory in the first place.
If you have any example scenes that demonstrate this issue, and are willing to share them for diagnostic purposes, please contact me, because I would like to resolve as many of these issues as possible before we release our next patch. You can reach me at devin.kendig@usa.chaosgroup.com. We now have a dedicated VfS for OSX developer, as well as a developer solely devoted to VfS for Windows. We are hoping we can resolve this issue, but it may require some work on the part of Trimble, to allow plugins such as V-Ray and Maxwell to utilize more memory than we are currently limited to.