In my humble 10+ years of using Workstation, I have never seen a BSOD crash in the guest or a BSOD in the host clearly due to running WS. I have seen WS guests hang (mostly linux guests), and I have seen the WS GUI disappear (while the machine was still running in the background, running WS again restores the UI so no work is lost). WS imho is a very mature product and so I think you are safe using it with confidence that you won't lose any work due to a sudden crash. However, from what I read it is advisable to leave room for the host to schedule things (so if e.g. you have 4 core CPU, assign only 2 on the guest) and also leave ample RAM for the host (i.e. assign as little RAM for the guests as possible - unless you have 8+ GB of ram installed).
Regarding the GPU, to my knowledge WS does not use it directly, but uses a special driver included in the VMware Tools, so the simple answer is that the guests do not have low-level access to the host's GPU and the risks for BSODs are minimal. This is not the case when you do need to use the host's GPU directly in a guest (for e.g. AI work) and you use GPU pass-through, where unpredictable things may happen. So, for normal WS use I think you are pretty safe to experiment.
