My perspective is if it works and your system is stable - it's great and no more dangerous than Write Caching in Windows. We are utilizing things in our systems that make them faster but adding degree of risk, like overclocking RAM/CPU/GPU, RAID-0, RAID controllers with cache and no BBU, huge amounts of non-ECC RAM... For SSD's write caching is great. It eliminates a lot of redundant writes and does write combining for what is actually gets written thus making it easier for SSD controllers and NAND itself.

I'm not concerned about FC and WC (Windows Cache) working at the same time. I barely ever see on 4GB equipped system my memory usage going near 3GB... For testing out FC, I will have 8GB of RAM. 3-4GB of that I will dedicate to FC with 30-60 sec flush interval. IMHO the rest 4-5GB for Windows itself is plenty.

Peace...